ISSN 1846-6168 (Print) ISSN 1848-5588 (Online)

TEHNIČKI GLASNIK - TECHNICAL JOURNAL

Scientific-professional journal of University North
Volume 13 Number 3
Varaždin, September 2019 Pages 165–259

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Legend:
(1) University North, (2) Mechanical Engineering Faculty in Slavonski Brod, (3) Faculty of Graphic Arts Zagreb, (4) Faculty of Civil Engineering Osijek, (5) Faculty of Engineering Rijeka, (6) Faculty of
Mechanical Engineering and Naval Architecture Zagreb, (7) Faculty of Metallurgy Sisak, (8) Tomas Bata University in Zlín, (9) Department of Physics of the University of Josip Juraj Strossmayer in
Osijek, (10) Faculty of Humanities and Social Sciences Osijek, (11) Karlovac University of Applied Sciences, (12) University of Applied Sciences Velika Gorica, (13) Department of Polytechnics - Faculty
of Humanities and Social Sciences Rijeka, (14) Faculty of Electrical Engineering and Computer Science - University of Maribor, (15) Faculty of Civil Engineering - University of Maribor, (16) University
College of Teacher Education of Christian Churches Vienna/Krems, (17) Mechanical Engineering Faculty Tuzla, (18) Mechanical Engineering Faculty Sarajevo, (19) University of Travnik - Faculty of
Technical Studies, (20) Higher Education Technical School of Professional Studies in Novi Sad, (21) University of Novi Sad - Faculty of Technical Sciences, (22) Faculty of Mechanical Engineering -
University of Montenegro, (23) Brno University of Technology, (24) Odessa State Academy of Civil Engineering and Architecture, (25) Faculty of Civil Engineering - University of Mostar, (26) Faculty of
Manufacturing Technologies with the seat in Prešov - Technical University in Košice

© 2019 Tehnički glasnik / Technical Journal. All rights reserved

 CONTENT

CONTENT I

NOTE FROM THE EDITOR-IN-CHIEF II

Sajjad DANESHPAYEH, Faramarz ASHENAI GHASEMI, Ismail GHASEMI

TENSILE PROPERTIES OF POLYPROPYLENE/LINEAR LOW-DENSITY POLYETHYLENE/NANO-TITANIUM DIOXIDE NANOCOMPOSITES USING A TWO- 165
LEVEL FACTORIAL EXPERIMENT

Majid AHMADI, Seyed Hadi SEYEDIN, Seyed Vahid SEYEDIN

INVESTIGATION OF THE MECHANICAL PERFORMANCE OF FIBER-MODIFIED CERAMIC COMPOSITES USING FINITE ELEMENT METHOD 173

Anđelko CRNOJA, Željko KOS, Oleg POPOV

APPLICATION OF A LOGARITHMIC MODEL ON A STRESS - DEFORMATION INTERDEPENDENCE OF THE RECYCLED TIRES 180

Erol CAN
POWER REGULATION BY COUPLE HALF WAVE LPWM RECTIFIER AT THREE-PHASE LOADS 184

Željko BARAČ, Ivan PLAŠČAK, Tomislav JURIĆ, Pavo BALIČEVIĆ, Vinko DUVNJAK, Mladen JURIŠIĆ, Goran HEFFER, Monika MARKOVIĆ
INFLUENCE OF AN UNEVEN SURFACE ON THE VIBRATION OCCURRENCE AFFECTING THE TRACTOR OPERATOR 192

Nuşin UNCU, Emine AVŞAR AYDIN

THE EFFECTS OF DIELECTRIC VALUES, BREAST AND TUMOR SIZE ON THE DETECTION OF BREAST TUMOR 197

Seyed Hadi SEYEDIN, Majid AHMADI, Seyed Vahid SEYEDIN

DESIGN AND CONSTRUCTION OF THE PRESSURE SWIRL NOZZLE AND EXPERIMENTAL INVESTIGATION OF SPRAY CHARACTERISTICS 204

Sanja ŠOLIĆ, Zdravko SCHAUPERL, Vlado TROPŠA

CUTTING PERFORMANCE OF DEEP CRYOGENIC TREATED AND NITRIDED HSS CUTTING TOOL INSERTS 213

Renata TOMERLIN, Mario TOMIŠA, Damir VUSIĆ

THE INFLUENCE OF PRINTING, LAMINATION AND HIGH PRESSURE PROCESSING ON SPOT COLOR CHARACTERISATION 218

Gordana JAUKOVIĆ
ADVANTAGES AND DISADVANTAGES OF RAMAN SPECTROSCOPY IN TESTING PAPER BANKNOTES 226

Mladen BOŠNJAKOVIĆ, Olivera MAGLIĆ, Dragomir MOŠKUN, Zoran CRNAC

VORTEX COOLED AIR TURNING OF INDUCTION-HARDENED RACEWAY ON THE WIND TURBINE-BEARING RING 230

Iryna SOLONENKO
THE USE OF CEMENT CONCRETE PAVEMENTS FOR ROADS, DEPENDING ON CLIMATIC CONDITIONS 235

Katarina PISAČIĆ, Marko HORVAT, Zlatko BOTAK

FINITE DIFFERENCE SOLUTION OF PLATE BENDING USING WOLFRAM MATHEMATICA 241

Krešimir BUNTAK, Matija KOVAČIĆ, Maja MUTAVDŽIJA

INTERNET OF THINGS AND SMART WAREHOUSES AS THE FUTURE OF LOGISTICS 248

Roman TRACH, Marzena LENDO-SIWICKA, Katarzyna PAWLUK, Nina BILOUS

ASSESSMENT OF THE EFFECT OF INTEGRATION REALISATION IN CONSTRUCTION PROJECTS 254

INSTRUCTIONS FOR AUTHORS III

TEHNIČKI GLASNIK 13, 3(2019), I-I I

 Note from the Editor-in-Chief

Note from the Editor-in-Chief *

Dragi čitatelji, manjkava.
- Osiguravanje stabilnog sustava financiranja – časopisi su
Dana 11. srpnja 2019. u Velikoj predavaonici Prehrambeno- suočeni s neizvjesnošću jer MZO često mijenja kriterije,
biotehnološkog fakulteta u Zagrebu, a na inicijativu prof. dr. sc. nisu unaprijed poznati iznosi potpore i hoće li je uopće biti,
Vladimira Mrše, glavnog urednika časopisa Food Technology a časopisi kao periodičke publikacije moraju imati
and Biotechnology (izdavač je Prehrambeno-biotehnološki stabilnost prihoda.
fakultet u Zagrebu), održan je inicijalni sastanak za pokretanje - Razmjena mišljenja i iskustava, te pružanja potpore
Udruge urednika i ostalih osoba uključenih u izdavanje časopisima u svim aspektima njihova rada.
hrvatskih znanstvenih i znanstveno-stručnih časopisa te onih za - Istupanje prema MZO, tijelima javne uprave, NSK, HR
popularizaciju znanosti. Sastanku je nazočilo preko 100 DOI uredu, bazama, vanjskim institucijama i dr.
zainteresiranih. Jedan od razloga za ovakvu inicijativu je i Javni - Promocija otvorenog pristupa znanosti u skladu s
poziv za financijsku potporu znanstvenim časopisima i preporukama Europske komisije objavljenima u "Planu S",
časopisima za popularizaciju znanosti u 2019. godini, objavljen prema kojima bi od 1. siječnja 2020. godine svi znanstveni
na stranicama Ministarstva znanosti i obrazovanja 12. lipnja rezultati proizašli iz istraživanja financiranih javnim
2019. (https://mzo.gov.hr/istaknute-teme/natjecaji-196/javni- sredstvima trebali biti objavljeni u časopisima u
poziv-za-financijsku-potporu-znanstvenim-casopisima-i- otvorenom pristupu – Hrvatska već ima, zahvaljujući
casopisima-za-popularizaciju-znanosti-u-2019-godini/1910). U dosadašnjem sustavu financiranja putem MZO, većinu
tom Javnom pozivu pod II. Korisnici financijske potpore je časopisa u otvorenom pristupu, pa je cilj Udruge održati
navedeno da "Pravo prijave imaju i znanstvene organizacije iz takav trend.
sustava znanstvene djelatnosti, odnosno ustanove upisane u
Upisnik znanstvenih organizacija osim javnih znanstvenih Radi pripreme dokumenata potrebnih za registraciju
instituta i javnih visokih učilišta jer su im troškovi izdavanja Udruge je nakon kraće rasprave i nominacije kandidata iz

* There is no English version of foreword because it is of local importance

znanstvenih i znanstveno-stručnih časopisa te časopisa za raznih područja znanosti predložena Radna grupa. Radnu grupu
popularizaciju znanosti prihvatljivi u sklopu programskog radi lakše operativnosti (čestih sastanaka) čine članovi iz
financiranja." Dakle, Sveučilište Sjever (izdavač časopisa Zagreba, a svrha je radne grupe da pripremi nacrt statuta koji će
TEHNIČKI GLASNIK) nema pravo prijave što mi je e-poštom poslati putem mailing lista svim urednicima na razmatranje i
iz MZO i potvrđeno. Jedna od primjedaba na sastanku bila je dopunu.
da je neprihvatljivo da MZO usred godine donosi odluku o Tijekom kolovoza je pripremljen nacrt statuta udruge koja
promjeni načina financiranja, radi koje je budućnost mnogih bi se trebala zvati "Hrvatsko udruženje za znanstvenu
časopisa upitna. Ti isti časopisi osiguravaju znanstvenicima komunikaciju" (skraćeno ZNAK, no to je samo prijedlog i još
vrednovanje njihovoga rada, a temelje se na volonterskom radu, nije konačno odlučeno da li skraćeni naziv ostaje).
bez sustavne potpore, pri čemu se ovakvim odlukama Mišljenja sam da TEHNIČKI GLASNIK svakako treba
omalovažava rad urednika i suradnika. Također je izražena i podržati osnivanje Udruge i biti aktivan u njoj, jer dugoročno
sumnja da se financiranje u 2019. godini može ostvariti putem može imati samo koristi od ovog članstva.
programskih potpora jer (navodno) ne postoje podaci o kojim
se iznosima radi, već se navodi izdavačka djelatnost kao jedna Srdačan pozdrav,
od stavki. Koje bi aktivnosti Udruge s početka ovog uvodnika
trebale biti? Istaknuto je prije svega sljedeće: Milan Kljajin, glavni urednik
- Sudjelovanje u održavanju sustava znanstvenog izdavaštva
– prije svega komunikacija između časopisa i MZO te
Povjerenstva za izdavačku djelatnost, koja je trenutačno

II TECHNICAL JOURNAL 13, 3(2019), II-II

ISSN 1846-6168 (Print), ISSN 1848-5588 (Online) Original scientific paper
https://doi.org/10.31803/tg-20190312191013

TENSILE PROPERTIES OF POLYPROPYLENE/LINEAR LOW-DENSITY

POLYETHYLENE/NANO-TITANIUM DIOXIDE NANOCOMPOSITES USING A TWO-LEVEL
FACTORIAL EXPERIMENT

Sajjad DANESHPAYEH, Faramarz ASHENAI GHASEMI, Ismail GHASEMI

Abstract: In this paper, a 23 factorial design analysis was used to study the parameters affecting the mechanical characteristics of polypropylene/linear low-density
polyethylene/nano-titanium dioxide (PP/LLDPE/TiO2) nanocomposites, and to optimize these factors in order to predict the maximum ultimate tensile strength (UTS),
elastic modulus (EM), and yield strength (YS) simultaneously. To do this, two levels of nano-titanium dioxide (TiO2), linear low-density polyethylene (LLDPE) and styrene-
ethylene-butylene-styrene (SEBS) as the coupling agent were selected and eight experiments were conducted for every response. The most effective factors influencing
the UTS, EM, and YS were found, and acceptable prediction regression models were taken. One noted that nanoparticles increased the elastic modulus. The attendance
of high levels of LLDPE and SEBS resulted in a decrease in YS and UTS. Moreover, the optimum values of variables were determined by using the contour plot.

Keywords: elastic modulus; factorial design; nanocomposite; polypropylene; tensile strength

1 INTRODUCTION styrene ethylene-butylene-styrene (SEBS) can be applied as

a coupling agent to improve the TiO2 surface [9-11].
Nowadays, polymeric products, especially polyethylene Many scientists have investigated the mechanical
(PE) and polypropylene (PP), are developed for their low properties of polymers and polymer composites. Garcia et al.
expense, good mechanical features, small weight, and other [12], for instance, added SiO2 nanoparticles to the PP matrix
desirable characteristics [1]. Different kinds of polyethylene, and observed that the impact strength and elastic modulus
containing high-density polyethylene (HDPE), low-density were improved. Selvin et al. [13] found that TiO2
polyethylene (LDPE), and linear low-density polyethylene nanoparticles significantly increased the elastic modulus of
(LLDPE) are used to improve the mechanical and physical the polystyrene matrix. Moreover, Sirirat et al. [14] added
characteristics of PP [2]. Additionally, LLDPE has numerous small values of TiO2 to the PP matrix and reported an
applications, and the importance of LLDPE has increased improvement in some mechanical properties of the based
due to its special characteristics [3]. material. Moreover, Altan [15] showed that, by embedding
To refine the particular characteristics of these polymers, TiO2 nanoparticles in the PP matrix, the elastic modulus of
several additives are mixed with them. Adding some micro- the structure increased, but its impact strength was reduced.
or nanoscale fillers may improve the disadvantages of neat Ternary nanocomposites, including a system of the
polymers. Nanocomposites are polymers that are embedded polymer matrix, elastomer, and filler, have newly been
with nanoscale fillers [4]. Polymer nanocomposites can incorporated in different applications [16, 17]. Liu et al. [18]
modify the mechanical strength, heat resistance, elastic showed that, by adding TiO2 nanoparticles to PP/LLDPE,
modulus, thermal degradation and viscoelasticity more than some mechanical properties of the compounds were
other traditional polymer composites [5]. By adding small enhanced. Furthermore, Abu Ghalia et al. [17] reported that,
values of nanoparticles, melt processing, polymer by embedding calcium carbonate (CaCO3) in PP/LLDPE
crystallization, and electric and thermal conductivity can be compounds, some of their mechanical characteristics were
improved [6, 7]. improved. Altan and Yildirim [19] showed that structures
Polymer nanocomposites have recently gained the including TiO2 and SEBS present better mechanical
attention of many material researchers. They usually study characteristics compared to ones without SEBS.
the effects of embedding various nanoparticles on the Guo and Li [20] found that SEBS/titania nanocomposites
characteristics of polymer materials. Organic and inorganic showed good mechanical attributes. They also reported that
nanoparticles can be utilized as reinforcement. Some of the the uniform dispersion of titania nanoparticles in the SEBS
most used inorganic nanoparticles are SiO2, TiO2, Al2O3, and matrix increased the thermal stability of samples.
ZrO2 [3]. TiO2 is a very special material due to special Additionally, Nguyen et al. [9] concluded that some
characteristics such as light density and thermal degradation mechanical characteristics of LDPE/modified TiO2
[8]. The main problem in manufacturing the TiO2 nanocomposites increased compared to the based
nanocomposite is its conflict with the polymer matrix, LDPE/unmodified structures. Xue et al. [21] verified that the
because TiO2 is hydrophilic and the polymer matrix is coexistence of organo-montmorillonite (OMMT) and nano-
hydrophobic. TiO2 nanoparticles also have a large surface Cu in Cu/OMMT/LLDPE nanocomposites may improve the
area ratio which makes them aggregate easily. To avoid this, anticorrosion properties of samples.

TEHNIČKI GLASNIK 13, 3(2019), 165-172 165

 Sajjad DANESHPAYEH et al.: TENSILE PROPERTIES OF POLYPROPYLENE/LINEAR LOW-DENSITY POLYETHYLENE/NANO-TITANIUM DIOXIDE …

Here, a 23 factorial design was used to supply a relation −1 and +1 range in such a way that the researcher could
for the YS, UTS, and EM of PP/LLDPE/TiO2 choose an experimental design from a list of designs.
nanocomposites as a mathematical function of parameters The 2k factorial design is one of the most widely applied
(SEBS, TiO2, and LLDPE). Moreover, the effect of every designs to investigate the effects of various parameters on a
agent on mechanical characteristics was studied and the particular response, where k is the number of parameters and
optimal range of each parameter was found in order to the base 2 shows the level of treatment for each discussed
achieve the best tensile properties. parameter [22]. The performed design is shown in Tab. 1
which briefly discusses the parameters and the change of
2 THE EXPERIMENTS their levels. Furthermore, different modes of combining
2.1 Materials materials via the software were determined. As presented in
Tab. 2, eight tests had to be prepared for each response
Polypropylene (PP-Z30S, MFR-25, 230 °C, 2.16 kg) and having three replicates.
linear low-density polyethylene (LLDPE-0209, MFR-0.9,
190 °C, 2.16 kg, and density of 0.920 gr ml-1) were procured Table 1 Level of factors applied to study the effect of LLDPE, TiO2 and SEBS
from the Arak Petrochemical Company, Iran. The nano-TiO2 Factors LLDPE TiO2 SEBS
−1 (low) 40 0 0
rutile structure with the mean size of 30 nm and density of Level
+1(high) 60 2 3
4.23 g/cm was obtained from the Iranian Nanomaterials
Pioneers (INP), Iran. Moreover, the KRATON polymer type Table 2 Results of running the software
G, namely styrene-ethylene/butylene-styrene (SEBS), was Full Factorial Design
used as a coupling agent. The compound was prepared by Sample No. 1 2 3 4 5 6 7 8
using a co-rotating screw extruder (ZSK 25 P8.2E WLE) PP (Wt. %) 80 60 78 58 77 57 75 55
LLDPE (Wt. %) 20 40 20 40 20 40 20 40
with a 170 to 190 °C temperature range. Next, they were TiO2 (Wt. %) 0 0 2 2 0 0 2 2
made as granules. Granules were injected with the help of an SEBS (Wt. %) 0 0 0 0 3 3 3 3
injection molding machine (IMAN MACHINE 125g) with Random order of samples 3 2 8 1 6 4 7 5
the temperature profiles of 190-200-210 °C, and the samples
were hence prepared. As three parameters at two levels were assumed, the
experimental design was named a 23 full factorial design that
2.2 Mechanical Testing needed eight test runs for every response. The average of
results is presented in Tab. 3.
The elastic modulus, yield, and ultimate tensile strength
were specified by a Zwick/Roell–Z100 machine (Germany) Table 3 The experimental results for YS, UTS and EM
Sample No. 1 2 3 4 5 6 7 8
due to the ASTM D638 standard with the strain rate of 50
YS (MPa) 19.63 12.9 15.33 11.56 21.86 13.33 16.16 11.9
mm/min at room temperature. Fig. 1 shows a sample before UTS (MPa) 23.63 19.5 21.86 18.3 23.93 18.03 20.33 19
and after the tensile tests. EM (MPa) 223 189 226.6 207.3 212 184.6 222.6 199.3

3 RESULTS AND DISCUSSION

3.1 Analysis of Variance (ANOVA) for Tensile Strength

The p-value is described as the minimum level of

importance leading to the rejection of the null hypothesis and
interaction is a kind of action that occur as two or more
objects have an effect upon one another [22]. F value is the
measure of variation in the data about the mean. Due to the
p-value described as the minimum level of importance
Figure 1 A sample before and after the tensile tests leading to the rejection of the null hypothesis, it seems that
the effect of every parameter was statistically important at the
2.3 Experiment Design p-value of less than 0.05.
The ANOVA results for YS are presented in Tab. 4. One
The factorial design of experiments (DOE) is a good and sees that LLDPE (P = 0.000), TiO2 (P = 0.000), SEBS (P =
well-known procedure of testing in which all parameters are 0.001), LLDPE×TiO2 (P = 0.000), and LLDPE×SEBS (P =
changed together in the experimental runs [22]. In this work, 0.021) with the p-values below or equal to 0.05 for a 95%
DOE was applied to study the effect of significant factors on assurance level should be statistically important for YS. In
the EM, YS, and UTS of PP/LLDPE/TiO2 nanocomposites. addition to that, Fisher’s variance ratio (F-value) is the
The main aspect in DOE is the choice of control factors [23]. amount of variability from the mean. Applying the F-value,
Here, the studied factors were LLDPE, TiO2 nanoparticles, the respective significance of each parameter and its
and SEBS. After the choice of factors, the 23 factorial design interaction would be:
method was offered the levels which were coded within the
LLDPE>TiO2>LLDPE×TiO2> SEBS>LLDPE×SEBS.

166 TECHNICAL JOURNAL 13, 3(2019), 165-172

 Sajjad DANESHPAYEH et al.: TENSILE PROPERTIES OF POLYPROPYLENE/LINEAR LOW-DENSITY POLYETHYLENE/NANO-TITANIUM DIOXIDE …

Table 4 ANOVA results for YS Relying on ANOVA for YS, UTS, and EM, a fitted
Source F P regression model with statistical importance was found as
Main Effects 249.31 0.000
LLDPE 555.84 0.000
follows:
TiO2 175.14 0.000
SEBS 16.95 0.001 Yield Strength = 15313 − 2.888LLDPE − 1.621TiO2 +
2-Way Interactions 21.94 0.000 0.504SEBS + 0.929LLDPE × TiO2 − 0.312LLDPE × SEBS
LLDPE×TiO2 57.56 0.000 (1)
LLDPE×SEBS 6.51 0.021
TiO2×SEBS 1.76 0.203
R-sq: 98.07%, R-sq(Pred): 95.67%, R-sq(Adj): 97.23%

The effects of the LLDPE×TiO2 interaction on YS are Ultimate Tensile Strength = 20.575 − 1.867LLDPE −
greater than the importance effect of a single-factor (i.e. 0.7TiO2 − 0.25SEBS + 0.642LLDPE × TiO2 (2)
factor SEBS). The important interaction of LLDPE and TiO2 R-sq: 98.28% R-sq(Pred): 96.13%, R-sq(Adj): 97.53%
shows that these parameters are related, i.e. if the level of one
parameter varies, the effect of the other one varies, too. Elastic Modulus = 208.08 − 13LLDPE + 5.92TiO2 −
The ANOVA results of UTS are presented in Tab. 5. It 3.42SEBS + 2.33LLDPE × TiO2 (3)
is clear that LLDPE (P = 0.000), TiO2 (P = 0.000), SEBS (P R-sq: 97.86%, R-sq(Pred): 95.18%, R-sq(Adj): 96.92%
= 0.003), and LLDPE×TiO2 (P = 0.000) whose p-values were
below or equal to 0.05 for UTS should be statistically From Eq. (2), one sees that all factors had a negative
important. Moreover, from the F-values in Tab. 5, the main effect on UTS. Thus, a lower factor setting (−1) would
relative importance of each factor and its interactions would result in a higher response. In the situation of Eq. (1), an
be: increase in LLDPE×TiO2 and SEBS from small to high levels
resulted in 2.77% and 6.76% increases in YS, whereas an
LLDPE>TiO2> LLDPE×TiO2> SEBS. increase in LLDPE and TiO2 resulted in a decrease in YS by
31.7% and 19.14%. Thus, LLDPE had a maximum effect on
Table 5 ANOVA results for UTS YS with a 31.7% contribution. In the case of Eq. (2), by
Source F P adding of LLDPE, TiO2, and SEBS decreased UTS by
Main Effects 261.86 0.000 16.63%, 6.58%, and 2.40%, respectively. Therefore, LLDPE
LLDPE 678.05 0.000 had a maximum effect on UTS with a 16.63% contribution.
TiO2 95.35 0.000
In Eq. (3), an increase in TiO2 and LLDPE × TiO2 from low
SEBS 12.16 0.003
2-Way Interactions 27.04 0.000 to high levels resulted in 2.57% and 5.85% increases in EM,
LLDPE×TiO2 80.12 0.000 whereas an increase in LLDPE and SEBS decreased EM by
LLDPE×SEBS 0.66 0.428 11.76% and 3.2%, respectively. Hence, LLDPE had a
TiO2×SEBS 0.34 0.569 maximum effect on EM with a 11.76% contribution.
A verified model must predict the response with good
Table 6 ANOVA results for EM accuracy with respect to the experimental data. Model
Source F P
Main Effects 235.29 0.000
adequacy is checked by R-Sq, R-Sq (adj), and R-Sq (pred).
LLDPE 553.29 0.000 A R-Sq value near 100% means a reliable fit to the
TiO2 114.57 0.000 experimental data [22]. Based on the ANOVA results, the R-
SEBS 38.20 0.000 squared of the regression equations was 98.07 % for YS,
2-Way Interactions 6.25 0.005 98.28% for UTS, and 97.86% for EM, which means that the
LLDPE×TiO2 17.82 0.001
LLDPE×SEBS 0.36 0.555
model is verified. The adjusted R-square was 97.23% for YS,
TiO2×SEBS 0.57 0.462 97.53% for UTS, and 96.92% for EM, which accounts for the
amount of predictors in the model. The prediction R-squared
The EM ANOVA results are presented in Tab. 6. It is statistic was calculated to be 95.67% for YS, 96.13% for
observed that LLDPE (P = 0.000), TiO2 (P = 0.000), SEBS UTS, and 95.18% for EM. Because the predicted R-square
(P = 0.000), and LLDPE×TiO2 (P = 0.001), whose p-values values were near the R-square and the adjusted R-square
were below or equal to 0.05 for EM would be statistically values for every response, none of the models appeared to be
important. Moreover, from the F-values in Tab. 6, the overfitting and none had an adequate predictive ability [22].
relative importance of each factor and its interactions would
be: 3.2 Main Effects and Interaction Plot for Yield Strength

LLDPE>TiO2> SEBS> LLDPE×TiO2. The main effects plot in Fig. 2 indicates that YS
decreases as LLDPE and TiO2 contents increase. Therefore,
The multiple regression analysis was performed on the the maximum YS of PP/LLDPE/TiO2 nanocomposites could
experimentally collected data for the YS, UTS, and EM of be found at a lower LLDPE and TiO2. Moreover, Fig. 2
the PP/LLDPE/TiO2 nanocomposites. Here, the analysis was shows that by increasing the amount of the SEBS factor
done by the Minitab® 16 software which applies the ordinary increases the yield strength. The relative strength of the effect
least squares technique to find the regression function. of different parameters can also be seen. The main effects

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plot for YS (Fig. 2) showed that LLDPE was the most 3.3 Main Effects and Interaction Plot for Ultimate Tensile
important factor. Strength
Fig. 3 shows the interaction plot between the three
discussed factors, namely LLDPE, TiO2, and SEBS for YS, The main effects plot in Fig. 4 indicates that increasing
respectively. The plots, known as interaction plots, are the amount of all three major factors, especially
employed to explain important interactions between process polyethylene, the ultimate tensile strength is reduced.
parameters. The interaction plot summarizes the interaction LLDPE decreased UTS for LLDPE, which was much
between the maximum and minimum amounts of each factor. smoother than PP. Therefore, the maximum UTS of
From these plots, one sees that the initial interaction PP/LLDPE/TiO2 nanocomposites would be reached at a less
happened between LLDPE and TiO2 for YS, demonstrated amount of LLDPE, TiO2, and SEBS. The relative strength of
by non-parallel lines. the effect of different parameters could also be seen. The
main effects plot for UTS (Fig. 4) showed that LLDPE was
the most important factor.

Figure 2 Main effects plot for YS

Figure 4 Main effects plot for UTS

Figure 3 Interaction plot for YS

According to Fig. 3, at a low level of LLDPE (20 wt. %) Figure 5 Interaction plot for UTS
and TiO2 (0 wt. %), the interaction was very important, but
adding both parameters produced a low interaction. Fig. 5 demonstrates the interaction plot between the three
However, the important interaction of LLDPE versus TiO2 discussed factors, namely LLDPE, TiO2, and SEBS, for UTS,
for YS showed that a lower TiO2 (0 wt. %) would result in an respectively. From the plot, one sees that the initial
improvement in the YS of PP/LLDPE/TiO2 nanocomposites interaction happened between LLDPE and TiO2 for UTS,
when factor LLDPE was under the low level (20 wt. %), showed by non-parallel lines.
while the influence of TiO2 was reduced at the high level of Fig. 5 shows that, at the low levels of LLDPE (20 wt. %)
LLDPE (40 wt. %). These data for YS suggested that the and TiO2 (0 wt. %), the interaction was very important, but
ideal TiO2 of PP/LLDPE/TiO2 nanocomposites differs from by adding both parameters, it produced a low interaction.
the LLDPE. The models with low TiO2 show a large YS However, the important interaction of LLDPE in respect to
when LLDPE is low, and the models with great TiO2 indicate TiO2 for UTS showed that lower TiO2 (0 wt. %) would result
a low YS when LLDPE is high. in an increase in the UTS of PP/LLDPE/TiO2
nanocomposites when LLDPE was under the low level (20

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wt. %), while the effect of TiO2 was reduced at the high level LLDPE was the most important factor. The elastic modulus
of LLDPE (40 wt. %). These data for UTS suggested that the of polymer nanocomposites largely depends on the good
ideal TiO2 of PP/LLDPE/TiO2 nanocomposites differs with dispersion of nanoparticles in the matrix. Fig. 7 shows field
LLDPE. The models with low TiO2 show large UTS when emission scanning electron microscopy (FESEM) images
LLDPE is low, and the models with high TiO2 demonstrate taken from the samples’ fractured surface. It can be observed
small UTS when LLDPE is high. from Fig. 7 that nanoparticles are well dispersed in the
matrix. As a result, titanium oxide nanoparticles lead to an
3.4 Main Effects and Interaction Plot for Elastic Modulus increase in the elastic modulus.
Fig. 8 illustrates the interaction plot between the three
The main effects plot in Fig. 6 indicates that the elastic investigated parameters, namely LLDPE, TiO2, and SEBS,
modulus decreased as LLDPE and SEBS varied from a low for EM, respectively. One could see that the initial interaction
to a high level. Consequently, the maximum elastic modulus happened between LLDPE and TiO2 for EM, indicated by
of PP/LLDPE/TiO2 nanocomposites could be obtained at non-parallel lines (Fig. 8). Fig. 8 shows that, at the low levels
lower LLDPE and SEBS. of LLDPE (20 wt. %) and TiO2 (0 wt. %), the interaction was
highly significant, and that increasing both parameters
produced a good interaction and increased the EM. However,
the important interaction of LLDPE versus TiO2 for EM
showed that a high TiO2 (2 wt. %) would result in an increase
in the EM of PP/LLDPE/TiO2 nanocomposites when LLDPE
was under the high level (40 wt. %), while the effect of TiO2
was reduced at the low level of LLDPE (20 wt. %). These
data for EM suggested that the ideal TiO2 of PP/LLDPE/TiO2
nanocomposites varied with LLDPE. The models with high
TiO2 show large EM when LLDPE is high, and the models
with low TiO2 indicate small EM when LLDPE is low.

Figure 6 Main plots for EM

Figure 8 Interaction plot for EM

3.5 Optimal Ranges to Achieve the Best Tensile Properties

Mini-tab uses a contour plot to obtain the optimal areas

of tensile properties. Contour or level plots are a method to
present a three-dimensional surface on a two-dimensional
plane. It graphs two predictor variables X Y on the y-axis and
a response variable Z as contours. In this graphs, darker
regions indicate higher responses values. They are beneficial
for the creation of a favorable response. They present the
Figure 7 FESEM image taken from fractured surface sample including 2wt.% TiO2 contribution of two parameters simultaneously, and another
nanoparticles parameter is retained at its middle level.
Fig. 9 presents the contour plot of the ultimate tensile
However, regarding the mechanical properties of the strength as a function of TiO2*LLDPE, SEBS*LLDPE, and
variables, namely EM, a variation of TiO2 seems to have a TiO2*SEBS. In any of these three modes, the third factor has
significantly increasing effect, similar to Selvin’s [13] been fixed in the middle level. Fig. 9 shows that to achieve
finding about polystyrene/TiO2 nanocomposites. The relative the best ultimate tensile strength, low amounts of LLDPE
strength of the effect of different parameters may also be (Less than 25 wt. %) and average amounts of titanium
seen. The main effects plot for EM (Fig. 6) showed that dioxide nanoparticles and SEBS should be used. B using this

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combination, the ultimate tensile strength of more than 32 been fixed in the middle level. It is clear that, to achieve the
MPa can be achieved. Based on Fig. 9, the presence of high best elastic modulus, low amounts of LLDPE and SEBS and
values of LLDPE (more than 35 wt.%) led to a significant high amounts of titanium dioxide nanoparticles should be
reduction in the ultimate tensile strength. used. By using this combination, the elastic modulus of more
Fig. 10 depicts the contour plot of the elastic modulus as than 220 MPa can be achieved. Based on Fig. 9, the presence
a function of TiO2*LLDPE, SEBS*LLDPE, and of high values of TiO2 led to a significant increase in the
TiO2*SEBS. In any of these three modes, the third factor has elastic modulus.

Figure 9 The contour plots of ultimate tensile strength

Figure 10 The contour plots of elastic modulus

Figure 11 The contour plots of yield strength

Fig. 11 presents the contour plot of yield strength as a 4 CONCLUSIONS

function of TiO2*LLDPE, SEBS*LLDPE, and TiO2*SEBS.
In any of these three modes, the third factor has been fixed in An optimization method, in which the factorial design,
the middle level. It is observed from Figure 11 that to achieve mathematical modelling and contour plots were used for the
more than 20 MPa for yield strength, the smallest amount of prediction of the mechanical properties of PP/LLDPE/TiO2
polyethylene (about 20 wt.%) with the highest amount of nanocomposites, has been studied. The following results
nanoparticles and compatibilizer should be combined. Based were obtained:
on Fig. 11, the presence of high values of LLDPE (more than - It was observed that the most important factors were
25 wt.%) led to a significant reduction in yield strength. LLDPE and TiO2, which influenced YS, UTS, and EM,
while SEBS was relatively less significant.
- From the main effects and interaction plot, one sees that
by adding SEBS from low to high levels, there was a

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6.76% increase in YS, whereas an increase in LLDPE led [11] Daneshpayeh, S., Ashenai Ghasemi, F., Ghasemi, I., & Ayaz,
to a decrease in YS by 31.7%. An increase in LLDPE M. (2015). Predicting of mechanical properties of
and SEBS decreased the UTS to 16.63% and 2.40%, PP/LLDPE/TiO2 nanocomposites by response surface
methodology. Compos. Part. B, 84, 109-120.
respectively. Moreover, an increase in TiO2 and
https://doi.org/10.1016/j.compositesb.2015.08.075
LLDPE×TiO2 (from a low to a high level) resulted in [12] Garcia, M., Vilet, G. V., & Jain, S. (2004). Polypropylene/ SiO2
2.57% and 5.85% increases in EM, respectively. nanocomposites with improved mechanical properties. Rev
- The optimized ranges of variables on the tensile Adv Mater Science, 6(2), 169-175.
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results show that the most improved tensile properties titanium dioxide filled Polystyrene microcomposites. Mater
were obtained in the low level of LLDPE and SEBS and let, 58(3-4), 281-289.
the middle level of titanium dioxide nanoparticles. https://doi.org/10.1016/S0167-577X(03)00470-1
[14] Wacharawichananat, S., Thongyai, S., & Tipsri, T. (2009).
Effect of mixing conditions and particle sizes of titanium
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Authors’ contacts:

Sajjad DANEAHPAYEH
Faculty of Mechanical Engineering,
Shahid Rajaee Teacher Training University,
Shabanloo St., Lavizan, Tehran, Iran
Tel: +9821-22970060
sajad_danesh66@yahoo.com

Faramarz ASHENAI GHASEMI

Corresponding author
Faculty of Mechanical Engineering,
Shahid Rajaee Teacher Training University,
Shabanloo St., Lavizan, Tehran, Iran
Tel: +9821-22970060
f.a.ghasemi@sru.ac.ir
faramarz_ashenai_ghasemi@yahoo.com

Ismail GHASEMI
Department of Polymer Processing,
Iran Polymer and Petrochemical Institute (IPPI),
15 km Tehran-Karaj Highway, Pajuhesh Science and Technology Park,
Pajuhesh Boulevard, Tehran 14977-13115, Iran
Tel: +9821-44787050/
I.Ghasemi@ippi.ac.ir

172 TECHNICAL JOURNAL 13, 3(2019), 165-172

ISSN 1846-6168 (Print), ISSN 1848-5588 (Online) Original scientific paper
https://doi.org/10.31803/tg-20181006143504

INVESTIGATION OF THE MECHANICAL PERFORMANCE OF FIBER-MODIFIED CERAMIC

COMPOSITES USING FINITE ELEMENT METHOD

Majid AHMADI, Seyed Hadi SEYEDIN, Seyed Vahid SEYEDIN

Abstract: Ceramic materials are widely used in impact safekeeping systems. Ceramic is a heterogeneous material; its characteristics depend considerably both on specifications
of its ingredients and the material structure completely. The finite element method (FEM) can be a useful tool for strength computation of these materials. In this paper, the
mechanical properties of the ceramic composites are investigated, and the mechanical performance modeling of fiber-fortified ceramic matrix composites (CMC) is expressed by
the instance of aluminum oxide fibers in a matrix composite based on alumina. The starting point of the modeling is an infrastructure (primary cell) that contains a micromechanical
size, the statistical analysis characteristics of the matrix, fiber-matrix interface, fiber, and their reciprocal influences. The numeral assessment of the model is done using the FEM.
The numerical results of composite elastic modulus were computed based on the amount of the added fibers and the porosity was evaluated for empirical data of samples with a
similar composition. Various scanning electron microscope (SEM) images were used for each sample to specify the porosity. Also, the unit cell method presumed that the porous
ceramic substance is manufactured from an array of fundamental units, each with the same composition, material characteristic, and cell geometry. The results showed that when
the material consists of different pores and fibers, the amount of Young’s modulus reduces with the increment of porosity. The linear correlation model of elasticity versus porosity
value from experimental data was derived by MATLAB curve fitting. The experimental data from the mechanical test and numerical values were in good agreement.

Keywords: ceramic composite; elasticity; fiber; Finite Element Method (FEM); mechanical performance; thermal stress

1 INTRODUCTION Ceramic matrix composites (CMCs) can be substituted

rather than other materials in various applications in which
Engineering materials are divided into three technical the higher expenses are offset by an increment in
sections; ceramics, metals, and polymers. Composite is a performance. They are prone to catastrophic failure due to
mixture of various materials from one or more of these parts. the lack of stiffness. To benefit from CMCs and minimize
One of the phases is often harder, discontinuous, and stronger problems like a partial failure, modeling and computational
named as the reinforcement. The less rigid and weaker phase software such as finite element analysis (FEA) are
is continuous termed as the matrix. The combination results fundamental for investigating stuff efficiency non-
in different premier properties are not displayed by unique destructively at the operating conditions and temperatures.
materials. The main advantageous property of composites is FEA is able to define mechanical characteristics, such as
mechanical efficiency. Composites contain reinforcement inter-laminar shear properties and shear forces, crack
(particles, fibers, flakes, and fillers) embedded in a matrix deflection, and congested damage failure [4, 5]. A new
(metals, polymers, or ceramics). The matrix retains the concept was developed by Tranquart et al. to model complex
reinforcement to form the desirable shape while improves all materials such as CMCs on the Yarn’s scale for identifying
mechanical properties. The important advantageous bending moment diagrams and qualitative data for life cycle
parameters of fiber-reinforced composites are specific anticipation, as well as material design and structure
modulus and strength, respectively [1]. optimization. A novel general finite elements approach
Ceramic pieces are broadly used in strike safekeeping (GFEA) such as the novel numerical modeling approach of
systems; the finite element method (FEM) is generally used the CMC yarn, as a suitable modeling scale, has been offered
for strength calculation. As ceramic is a heterogeneous recently. This model depends on a pattern-based explanation
material, its properties depend extremely both on of the micro-scale put into a GFEM-like framework. A multi-
characteristics of the material structure and on its scale and multi-physics macroscopic structure (model) of
components entirely [2]. Aluminum silicate is used in both the engineering or mechanical action or behavior and
metallurgical, pottery, glass, and ceramic industries for its the age of self-treatment CMC structures was offered by
resistance or durability. These materials contain refractory Genetetal and accredited on the stuff level. The mechanical
soils or clay content. The layered clay stone increases model considers the fracture or crack networks, as well as its
refractories resistance in high-temperature compositions that relation with fiber-matrix interrupting through fracture and
have a large granule or particle size distribution (PSD) with inelastic stresses or strains. All the simulations have been
high porosity and heterogeneous microstructure. Fiber- accomplished through the conventional software package in
modified composites use has been extended in the world due mechanical engineering such as ABAQUS/Standard FEA [6,
to ductility, durability, high strength, stiffness, and impact 7].
resistance. The major objective of the fiber addition is to Composites are superior to all other known structural
enhance the mechanical characteristics, strength in particular materials in distinct hardness fatigue strength, resistance,
[3]. high-temperature durability, and other properties. The
expected combination of properties can be fitted in advance

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and realized in making a specific material. Many modern possible: (1) a parallel arrangement of the fiber longitudinal
technologies need materials, such as metals, ceramics, metal axis in a single direction; and (2) an accidental adjustment.
alloys, and polymeric materials with unique combinations of Mechanical reactions of this unique composite depend on
properties that cannot be carried out. The required composite multiple parameters, such as strain-stress behaviors of the
materials for underwater, aerospace, and transportation matrix phases, fiber, the phase volume fractions, and the
applications have unique properties. Most of the composites direction a load or the stress is enforced to it [10]. In recent
typically have one construction in common, a binder or years, ceramic material has become increasingly substantial,
matrix mixed with a fortified material. A composite is a especially for unique uses that need great strength. Ceramics
material developed from two or more distinct phases, matrix show superior behavior at high temperatures in general. The
and dispersed. If the fibers are directionally oriented and difficulty of using ceramics is their fragile harm behavior. A
continuous, the material is called an advanced composite. single deficiency or defect can cause fragile damage in the
The composite material properties depend on the stiffness of whole structure [11].
bonds and the physical-mechanical features of their Fiber-reinforced or -modified composites have great
components. A specific advantage of composites is the mechanical performance, such as high unique strength and
capability of their components to be utilized fully. Such hardness. Particularly, laminated composite structures have
materials may take specified valuable properties that are not widely been used, where the in-plane properties are
found in the components. To obtain the optimal characteristic substantial [12].
in composites, their components are selected to have strongly In past decades, the finite element method as an efficient
various but perfect properties. The basis or matrix of tool has become a broadly accepted computational technique
composites may consist of metals or alloys (metallic not only in computational mechanics but also in certain
composites), carbon, polymers, and ceramics (non-metallic engineering majors. The approach has been extended to solve
composites) [8]. Technologically, the most substantial easy linear equations in mechanics of solid bodies along with
composites are generally those in which the dispersed phase severe non-linear problems in almost all fields of applied
is in the form of a fiber. Indeed, the powerful fibers physics or mathematics; and more recently, in many other
embedded in a softer matrix produce products with great branches of general science.
strength-to-weight proportions. The matrix materials Some packages that can be used are FLUENT,
transmit the load to the fibers that absorb the stress. ABAQUS, ADINA, ANSYS, NASTRAN, and LUSAS.
Also, the linear behavior of ordinary composites and its Finite element method gives a proximate distribution of the
frame and structure can be described analytically by Classical needed size in the considered field that is not possible to be
Laminate Theory (CLT). By investigating elastic mechanical specified analytically. A proximate solution is derived by
characteristics (Young’s moduli parameter, shear modulus of dividing the total area (bodies) to the minor elements. Then,
rigidity, and Poisson’s ratios), as well as influence of the related physical rules are applied to each element and
moisture and thermal impact, CLT can effectively compute total elements of the set of solutions to solve the existing
the stress-strain relations in composite become laminated up problems [13]. One of the novel numerical simulation
to fracture initiation. Through thickness, both the vertical and methods is finite element analysis (FEA) that can evaluate
shear forces are ignored in CLT, thus supposing composite the fracture probability caused by the characteristics and
plates to be extremely wide and long that causes neglecting performance of flaw distribution. It is considered an effective
edge effects. Finite element modeling (FEM) dominates tool to facilitate and increase the use of ceramics in
these issues and can perform the stress investigation of components and members; the FEA can also forecast the
structures more carefully. Computational or numerical distribution of ceramic rigidity. Specifically, the needed data
simulation results are being generally used in the design, on the microstructure distribution (i.e., relative density,
production, and investigation of several composites and porosity, and grain size) are used as the input parameters
structures. The important parameter in increment of [14]. Also, the finite element method is done to model the
industrial competitiveness is saving or reducing the design piezo-laminated plate panel as an appropriate composite
age. The capability to finish designs by a proper software on structure and show the static and dynamic analysis of
the computer effectively reduces the reliance on long-time structural vibrations subjected to an external force. The
methods and costly physical experiments. Composites can be piezo-laminated structure modeling is based on the
nearly optimized for suitable and special uses. Most assumptions of first-order shear deformation theory (FSDT)
commercial FE software possess user-friendly composite [15]. In general, the purpose of the numerical model is to
mathematical modeling capabilities, which can accurately investigate the effect of substantial parameters on the
obtain elastic action through anisotropic or orthotropic behavior of the fiber composite. This grid frame or
constructional modeling. Unlike CLT, FE models allow substructure (elementary cell) takes fiber, the fiber-matrix
accurate and regular stress analyses through the interface, the single components matrix, and their particular
accomplishment of an appropriate computerized sample harm behavior into an account. It is selected in such a way
model, leading to the anticipation of stress concentrations [9]. that a macrostructure property for the complete structure can
The arrangement or orientation of the fibers, the fiber be made by a proper number of substructures. The model has
density, and their distribution all have a significant influence been performed in a finite element method code to research
on the resistance and other performances of fiber-modified the effect of separate component factors on the behavior of
composites. With regards to direction, two extremes are the total.

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In a finite element method modeling, several analyses and elasticity. This study focuses on the mechanical
can be done; for instance, dynamic and static analysis, which performance of ceramic composites as well as the
later could be modeled and involved forced vibrations. In comparison of experimental data and simulation results.
general, a static linear elastic analysis is the easiest and
default one but with limited use due to its closed scope [16]. 1.1 Methodology
Modeling of the accidental fiber distribution of a fiber-
resistant composite via simulation software is of high The present study deals with technical performances of
importance to investigate the approaching failure behavior of the elastic theory originated from FEA of the total
the material on the limitation of micro-scale. Fiber-reinforced representative volume elements in fiber-modified
composites are typically recognized as ordinal materials with composites. The fibers are put orderly in the square array that
three structural levels: macro-scale, mesoscale, and micro- is known as the uni-directional composite. An example of a
scale. The micro-scale defines the adjustment of composite uni-directional fiber composite is shown in Fig. 1.
fibers in the fiber bundle. The mesoscale typically relates to
the fabric/lamina shape or geometry, and the macro-scale
composite refers to engineering the structural action of the
stuff. In a multi-scale modeling and simulation of composite
stuff, micro-scale concepts (including both numerical-
analysis and mathematical methods) are usually applied to
anticipate the effective rigidity and strength performance of
axial symmetry of a composite material or transversely
isotropic fundamental properties of composites, which are
used as theoretical tools for technical structure design [17,
18]. Recently, a finite element analysis (FEA) modeling has
been performed for the long fiber- modified ceramic matrix
woven composites (LFMCWCs) sample. For instance, this
method has been validated to investigate the grinding process Figure 1 The schematic image of the unit cells.
of a 2.5D woven quartz such as fiber-reinforced silicon
dioxide ceramic matrix (SiO2/SiO2) composite. Concerning It is supposed that the fiber and matrix material is usually
the grinding tests, their results were directly confirmed for linearly elastic. Typically, a unit cell is employed for the
the precision of the FEA method [19]. analysis. The measure of the fiber volume in proportion to
The strength of these studies is their uniqueness, using the whole volume of the composite is served from the cross-
various materials and composites, as well as FEM use as a sectional areas of the fiber associated with the total cross-
useful tool to analyze and predict the mechanical sectional area of each unit cell. This fraction of composite is
performance of composites, which is a cost-effective and considered as a substantial parameter in a composite that is
time-saving approach. However, the past research named the fiber volume fraction (VF).
weaknesses are testing only a few limited materials and some
simulations without comparing with experimental data, in 2 EXPERIMENTAL METHOD
particular, microstructure SEM images that are very vital for
investigating mechanical performance. Some samples were made using the layered claystone,
In the present research, only one composite has been clay, and bauxite in the amounts defined by the Jahad
modeled with a total detailed account of its physical Daneshgahi Corporation according to scientific principles
morphology along with its thermo-physical performances. [21, 24]. Samples with the addition of 1% wt. content of low
The composite morphology at micro-scale has been made as alumina-based fibers (with the aspect ratio of l/d ≈ 17), were
close to reality as possible with measurements from SEM added to the composition in order to evaluate the results of
micrographs for the geometric details, such as the fiber radius numerical modeling to the empirical data. The material was
and length. A commercial FE code of ABAQUS has been blended in the ball mill with water to enable better
applied to create the computational model. The real distribution of components, proper fibers in particular. The
microstructure with fiber distribution has been specified via obtained composition was dried within 24 hours at 100 °C
an SEM image, for example. The science of image analysis and then pressed between pressures of 35000 kPa to 55000
has then been done on the main image to determine the fibers kPa to create two various porosities. Other samples were
based on various color threshold modules, histograms and thermally operated at about 1200 °C and then were tested via
algorithms. From this image, the data such as the distribution the compaction and the Brazilian tests [20] to get the values
of distances between neighboring fibers and the fiber radius of elasticity modulus (E) and strength (F). The test was done
extracted based on image pixels in a black and white image via the modern-hydraulic testing system (Instron testing
via MATLAB image processing toolbox. The obtained system, Model 1362) with a load cell of 5000 N and 100 kN
statistical parameters were utilized and employed mesh grids through a data logger. The calculated values of modulus were
to generate a finite element analysis that was used to served to evaluate the numerically obtained values [21]. The
anticipate the effective mechanical property and compare it whole samples were experimented using the scanning
with the experimental data, such as volume fraction, porosity,

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electron microscope (SEM), and captured images were of the fibers was chosen while making the material and fixed
employed to determine their porosity [22]. on 1% volume. The fiber dimensions were obtained by
Porosity values were measured based on the various evaluating short fibers via the image processing program.
threshold level of darkness of the obtained images via the According to Fig. 1, the average fiber length was 0.1344 mm,
image processing method. Different SEM images of each and the average fiber radius was 0.003 mm. Thus, the
sample were used to determine the porosity of various formula for calculating the volume of the single cylindrical
samples. This method is appropriate since the pore, absorbs fiber was computed as follows:
more light, and it takes place as part of the image darker than
of the solid material. Given the porosity of the material and π r 2l =
Vf = π (0.003) 2 × 0.1344 =×
3.8 10−6 mm3 (1)
the proper method for determining the number and share of
pores, given in Fig. 2, the microstructure images were
The material volume was computed from total fiber
captured using an SEM system, (the Zeiss DSM-960A
constituents using the simple equation based on the cell
model, operated at the range of 21 kV).
volume of 0.0000038 mm3 and edge length of 0.068 mm.
Since the fiber length is 0.1345 mm and also the unit cell can
be big enough, the fiber can fit in each cell. The presumption
that eight fibers belong to one elementary cell provides a
cube with the dimensions of 0.14 mm × 0.14 mm, and the
depth of 0.14 mm; also, the fiber radius is r = 0.003425 mm,
and the length is l = 0.137388 mm. They are the same for
entire fiber volume fractions. The calculated volume
fractions of elementary cells for various fibers have an error
range of 0.04-0.1 in proportion to various fiber volumes in
ceramic.
All fibers were randomly put into a matrix, which
included 4 and 8 fibers. The schematic representation of fiber
has been shown in Fig. 3.

Figure 2 The digital image for micromechanical modeling of an accidental

descriptive volume element in a composite. The SEM image is taken from [22].

2.1 The Explanation of the Finite Element Analysis

The unit cell approach supposes that the porous ceramic

has been made of an array of fundamental elements or units,
each with the same composition, cell shape or geometry, and
material characteristics. A plate cubic cell is investigated as Figure 3 The schematic diagram of the designed ceramic composite system.
a descriptive volume element to model and simulate the real
microstructures of porous ceramics. This simulation To investigate the effect of porosity on mechanical
supposes that: a) the ceramic matrix is investigated as being characteristics, the elementary cell was produced with fibers
isotropic; b) the elastic performance of the ceramic without pores and cells that were put into the pores.
composite is linear [6, 25]. The schematic representation of the mesh grid according
Total 3D finite element (FE) simulations were generated to the unit cell has been shown in Fig. 4.
using ABAQUS 2018, FE software package. Total material
data was used for FE simulation and the matrix:
For fibers: the first Young’s modulus E1 = 145000 MPa
and Poisson’s ratio of ν1 = 0.25; the second Young’s modulus
E2 = 10000 MPa with Poisson’s ratio of ν2 = 0.20.

3 RESULTS AND DISCUSSION

The mesh geometry was generated by computational cell

elements derived from image processing of the material
SEM, and certain calculations were done based on the Figure 4 Schematic representation of the finite element unit cell
combination of the material. Moreover, the volume fraction

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Fig. 5 shows the unit cell: a) the fibers with pores (porous been reported in Tab. 1 according to the density (without
fibers); and b) the fibers without pores. It can be realized that pores) from the Tab. 1.
the existing contact between matrix and fibers is the surface
to surface contact type with a friction factor of 0.1. In the Table 1 Physical properties of alumina (Al2O3).
software, it is determined that the surface to surface contact 𝜌𝜌 Cp Λ E ν Α
(g/cm3) (J/g·K) (W/m·K) (GPa) (1/K*106)
is as of the finite sliding and the friction formulation as of the 3.989 0.78 29 390 0.22 9.1
penalty.
Fig. 6 shows the matrix with 8 fibers. This model of
3.1 Calculation of Mechanical Properties by Analytical elementary mesh grid cell is originated from the matrix in
Solution which it does not have any pores.

The mechanical performance of the lamina is computed 3.2 Comparison of Experimental and Calculated Parameters
using the following equations of Elasticity Theory, as well as of Elastic Modulus
Halphin-Tsai’s formulae; Linear Young’s Modulus equation
in the fiber for each direction is as follows: To evaluate the achieved numerical simulation results,
the derived data were tested and analyzed via a mechanical
σ experiment. The obtained values of elastic modulus for
E= (2)
ε various combinations are divided into two main parts: one
with only pores, and one with fibers and pores
σ is the stress, and ε is the strain in each direction (x, y or z). simultaneously, which are shown in Fig. 7. The experimental
data were also added to the data diagram and fitted with the
model extended in this study. When the material consists of
ε2
ν 12 = − (3) pores and fibers, the quantity of Young’s modulus reduces
ε1 with the increment of porosity. The value of Young’s
modulus in the improved material with fiber has greater
ε1, ε2 are the strains in various directions (x, y, z). amount as compared to the material without fiber including
the same porosity. Poisson’s ratio, generally, decreased with
an increasing fiber volume fraction according to Eq. (4).

ν vf Vf + vmVm
= (4)

In this equation, νf is Poisson’s ratio of fiber, and νm is

Poisson’s ratio of a matrix.

Figure 5 Elementary cells: a) with fibers and pores; and b) with fibers without
pores.

Figure 7 Young's modulus of elasticity versus the porosity volume.

Figure 6 The impact of the load on the elementary cell. Fig. 8 shows the linear regression model of the elastic
modulus obtained by the experimental data.
Experimental data for pure Al2O3 used to simulate the This linear correlation was calculated by MATLAB
alumina ceramic are summarized in Tab. 1. It should be noted software of version R2014b as follows:
that the physical properties of the material (Density ρ,
Specific heat Cp, Thermal conductivity λ, Young’s modulus ε+
−0.08871 10.27
E= (5)
E, Poisson’s ratio ν, and thermal expansion factor α) have

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with the results obtained from the experimental data. In

addition, it was found that the mechanical properties of a
ceramic composite such as E, ε, σ , and ν are strong functions
of volume fraction in the fibers. The results showed that any
change in the dimension or volume and porosity of the fibers
could influence the mechanical properties of a composite.

4 CONCLUSION

The finite element method, as a useful model, is a

Figure 8 Linear curve fitting model of elasticity versus porosity value (%). powerful tool to investigate the different properties of
composite materials. The effect of resistance, stiffness, and
In this equation, E is elastic modulus (GPa), and ε is reinforcement distribution in mechanical properties of
porosity volume (%). Eq. (5) signifies that with increasing composite material is considered by checking the finite
porosity volume, the modulus of elasticity decreases. The element analysis and micromechanics approach.
experimental data shows good consistency with the linear In this study, the geometry of the mesh was obtained
model. Also, the statistical parameters verify the accuracy of through calculating elements of unit cells, which had been
the experimental results. The quality of fitness is presented obtained from image processing; it is used for the analysis of
in Tab. 2. the material SEM images, as well as certain calculations
based on the material performance. The information obtained
Table 2 Statistical data calculated by MATLAB software. from the mechanical analysis test was employed to evaluate
Statistic parameter Calculated value the achieved simulation results. The experimental data was
SSE 0.003024
also added to the data diagram, and the information fitted the
R-Square 0.975800
Adjusted R-Square 0.951600 FEM simulation model was extended in this research. The
RMSE 0.054990 results showed that when the material consists of pores and
fibers, the index of Young’s modulus reduces with the
Compared to the experimental values derived from increment of the porosity. The value of Young’s modulus of
mechanical experiment, it presents good consistency of either enhanced or fortified material, including fibers has
experimental and calculated values in the model. greater values compared to the material without fiber with the
Schematic flowchart for preparing samples of each same porosity. The linear model of the elastic modulus,
experiment is shown in Fig. 9. which was obtained by the experimental data and was
compared to empirical values originated from a mechanical
test, signifies good consistency with those computed values
of the mathematical simulation model.
The numeral model was extended based on the
investigation of mechanical behavior, parallel to measured
porosity properties, and a linear mathematical model was
derived for elasticity modulus with appropriate accuracy by
experimental data. The number of entire fibers was prepared
in each experiment in the cube related to the combination of
the material. The used materials were examined
mechanically and by means of simulation results in order to
get the key values of elastic modulus, physical and
engineering properties, as well as the structure, which was
tested by the image processing analysis of the SEM images.
The number and size of the pores and porosity were the basis
for calculating the proper elementary cube for computer
simulation. Finally, the experimental and simulation data
were in good agreement.

Acknowledgments

Figure 9 Schematic flowchart describing the experimental procedure of samples. This research has been guided and supported by a
professional mechanical engineer, Seyed Hassan Alhoseini.
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ISSN 1846-6168 (Print), ISSN 1848-5588 (Online) Original scientific paper
https://doi.org/10.31803/tg-20190707102048

APPLICATION OF A LOGARITHMIC MODEL ON A STRESS - DEFORMATION

INTERDEPENDENCE OF THE RECYCLED TIRES

Anđelko CRNOJA, Željko KOS, Oleg POPOV

Abstract: During the last two decades, technological development has led to an extreme increase in transport and connected industries. This has significantly increased the
production of automobile tires, which have their life span after which they go to waste. It is therefore necessary to extricate new products from recycled raw materials. For a product
to be created, it is necessary, especially in civil engineering, to examine and determine all the properties of this material (pressure, traction, stress resistance, etc.). The results
obtained by the research in this paper are mathematically processed by applying a logarithmic model. The aim of this process is to predict stress deformation in terms of tensile
force. The model obtained is significant with accuracy of 87.21% and has a very high accuracy of the deformation estimation in relation to the applied stress. Independent variables
were granulometric composition, binder (glue) and specific mass.

Keywords: deformation; logarithmic model; recycled rubber; stress

1 INTRODUCTION is in the north-western Croatia [8]. Used tires are mostly

collected from a wider area. This is important because every
For a long time, it was deliberated how to recycle the production facility has different technology, access, quality,
vehicle tire to create new products in many areas of human granulometric composition, quantity and type of binders
activity and because of the rubber properties, the same (glues) used, and other parameters that are specific to the
applies for civil engineering and construction industry. After individual manufacturer, reflecting the quality of the raw
the establishment of technological recycling processes, we material to produce samples/products. The geographic
started investigating the effects on human health. One of the position of producers and collectors of spent car tires in the
main reasons for the recycling process is the procedure for world is an important fact because the various climatic
disposal’s harmful impact on the environment, nature and impacts, traffic management arrangements, etc., are
human health as it is complicated and the waste is determining quality of tire and tire composition for a wider
environmentally hazardous [1]. Certain authors tell us about area of tire use.
the performance of certain rubber components on human
health and its association with the occurrence of certain 2 MATERIAL AND METHODS
diseases [2-6]. The beginnings of recycling were in the 2.1 Basic Features of the Application of a Mathematical
United States in the 1960s and in Europe, recycling of tires Logarithmic Model
began in the 1980s [7]. The first products that were produced
from recycled vehicle tires were developed by the The tests were carried out on the axial device for the
construction industry, and were mainly rubber floors for application of tensile force in terms of the test of resistance
sports grounds. Different methods are being developed today to stretching. Test details can be found in Fig. 1.
and different technological processes are sought – those that
can produce products widespread in different sectors of the
economy, especially in civil engineering as an engine of the
overall economy. It is very important to know the properties
of each material so that its behavior can be determined in
different situations. When performing the test, the
measurement procedures should be carried out according to
the applicable norms in order to be comparable and useful.
Such results should be dealt with from various aspects to
obtain relevant and correct information that is especially
important when new products in construction industry are
developed and that tells us what material it is and what kind
of properties it has. The aim of this study is to show results
and to direct further research towards proving that the
products from recycled automotive tires have potential and
that such waste from the environment can and should become
a source of raw materials for wider application. It should be
noted that the geographical location of the recycling facility Figure 1 Sample testing

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The results were processed using a logarithmic model. The amount of binder (polyurethane adhesive) ranges
Such a model is applied when we have multiple independent from 29.6 to 67 kg/m3 of the sample. A single manufacturer
variables each of which is subject to logarithm. Then, control may use a different type of binder within the material
of the model is done in terms of its correctness, significance, structure. The tested samples are based on polyurethane-
etc. Such actions are needed to prove its realistic application. based glue, while other binders such as epoxy can be used,
The proposed model predicts with certain accuracy the etc., which is especially important in civil engineering,
deformation of the real sample in relation to the assumed because of the economical acceptance, e.g. production of
stress provided that the known values for the specific mass construction panels for improvement of soundproofing
and binder amount are known. The minimum accuracy must properties on light metal structures and construction panels
be 80% to make the model applicable and acceptable. In such for making roadside sound barriers.
conditions we get a mathematical expression so that the
mentioned sizes can be calculated. 2.3 Results of Samples Testing

2.2 Main Characteristics of the Test Samples Twenty-seven samples were tested with different
properties. The changing variables are the granulometric
The samples were manufactured according to the valid composition, the specific weight, and the amount of the
norm [9] and as such were tested on the axial device. Load binder. In Fig. 3 we can see a graphic representation of the
appliance is manual, and monitored and read through stress ratio and the associated deformation of a particular
measuring devices. The following figure shows the test sample. In the same figure it can be noticed that there are
specimen according to HRN EN ISO 527-4: 2008 (for testing significant differences in values and that the influence of
of the tensile strength of polymeric materials) [9]. The individual variables in the sample on the results of the test is
detailed dimensions of the sample are shown in Fig. 2. visible.

Sample thickness
10 mm
15 mm
20 mm

Figure 2 Test sample

Samples were prepared according to the following

different characteristics:
1) Specific mass
2) Granulometric composition
3) The amount of binders
4) Geometric Characteristics (Sample Thickness).

The specific mass ranges from min 585 kg/m3 to max

1100 kg/m3.
The granulometric composition is divided into 3 groups,
namely: Figure 3 Test results - stress and deformation relationship
1) A granulate of 0.5-2.0 mm
2) A granule of 2.0-3.5 mm 3 APPLICATION OF THE MATHEMATICAL MODEL
3) Granulate mix (0.5-2.0-35% + 2.0-3.5-65%).
Based on the results presented, we created a database and
Plan of experiment is listed in Tab. 1. used the Statistical Package (SPSS) program with the
application of a multiple logarithmic model.
Table 1 Plan of the experiment In the model shown in Tab. 2, we see that all variables
Number of
Sample thickness Granulometric composition
experiments are logarithmized. It should be emphasized that the
10 mm 0.5 – 2 3 respective variables are independent of each other, which is
10 mm 2 – 3.5 3 one of the conditions for applying the chosen model. The
10 mm 0.5-2(35%) + 2-3.5(65%) 3 variables that are considered are the following:
15 mm 0.5 – 2 3 1) log(δ) - logarithm variable "stress"
15 mm 2 – 3.5 3
15 mm 0.5-2(35%) + 2-3.5(65%) 3 2) log(ρ) - logarithm variable "specific mass"
20 mm 0.5 – 2 3 3) log(pu) - logarithm variable "polyurethane glue –
20 mm 2 – 3.5 3 binder".
20 mm 0.5-2(35%) + 2-3.5(65%) 3
Total 27 The model interprets the accuracy of 87.21% (R2 =
0.87212527) in relation to the given results. This means that

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 Anđelko CRNOJA et al.: APPLICATION OF A LOGARITHMIC MODEL ON A STRESS AND DEFORMATION INTERDEPENDENCE OF THE RECYCLED AUTOMOBILE …

with an accuracy of 87.21% we can predict the deformation such as specific mass and amount of binder, must remain
results in relation to the predicted stress if we apply this invariable, otherwise the model is not valid and cannot be
model. It should be noted that other independent variables, applied.

Table 2 The logarithm results of the test result database

Regression Summary for Dependent Variable: log deformation (Database) R = .93387647, R2 = .87212527 Adjusted R2 = .87059077 F(3.250) = 568.35 p
b* Std. Err. - of b* b Std. Err. - of b t(250) p-value
Intercept 1.49231 0.015047 99.1744 0
log(δ) 1.015547 0.024731 1.29961 0.031649 41.0636 0
log(ρ) (t/m3) −0.304961 0.02444 −1.28938 0.103332 −12.478 0
log(pu) g/m2 −0.083137 0.02291 −0.13434 0.03702 −3.6289 0.000345

3.1 Testing Models of Expectation or Significance fulfilled, and we conclude that the model is correct and
reliable.
Testing the significance of the model is carried out to
determine the level of significance of the test. The test Table 5 The results of logarithm test results base-heteroscedasticity
Spearman Rank Order Correlations (Spreadsheet 14) MD pairwise
provides the information with which reliability is performed.
deleted Marked correlations are significant at p < .05000
If the data is such that the probability value of p < 0.05 we Valid - N Spearman - R t(N−2) p-value
say that the results are acceptable. Residuals &
254 0.032002 0.508281 0.611701
log(δ)
Table 3 The test results of the logarithm results-significance base Residuals &
254 0.024431 0.387948 0.698382
Analysis of Variance; DV: log deformation (Database) log(ρ)
Sums of - Mean - Residuals &
df F p-value 254 0.002687 0.042648 0.966016
Squares Squares log(pu)
Regress. 26.65913 3 8.886378 568.3461 0
Residual 3.90888 250 0.015636 4 MATHEMATICAL MODEL RESULTS
Total 30.56801

According to Tab. 3, the value of factor p is less than After making the logarithmic mathematical model and
0.05, and we conclude that the model is correct and reliable. performing the tests to verify the correctness of the applied
model, we conclude that it can be applied with a very high
3.2 Model Multicollinearity Test accuracy to predict deformation with known stress. The
condition is that the independent variables of the specific
Multicollinearity testing is performed to determine the mass and amount of polyurethane adhesive are known and
correlation of independent variables, or to show us what is unchangeable. This is ensured by the technological process
the interdependence of the same. of production for a given product. Based on the above-
mentioned requirements, the model defined the mathematical
Table 4 The results of the logarithm test results base-multicollinearity expression that we can use to make such calculations. By
Variables currently in the Equation; DV: log deformation studying the results of the multiple logarithmic model, we
(Crnoja database 25.05.2019.) came to the following mathematical expression:
Tolerance Logarithmic form of equation:
log(δ) 0.836293
log(ρ) (t/m3) 0.856332
log(pu) g/m2 0.97453 logε =
1.49 + 1.2996logδ − 1.289logρ − 0.134logpu (1)

For multicollinearity analysis it is important that all Basic form of equation:

factors are greater than 0.20. If we look at the model in Tab.
4, we see that the condition is fulfilled, and the conclusion is ε = 31.07δ 1.30 ρ −1.29 pu 0.134 (2)
that there is no multicollinearity problem.

3.3 Testing the Model for the Presence of Heteroscedasticity Where: ε – deformation, δ – stress (MPa), ρ – specific mass
(t/m3), pu – glue g/m2 (kg).
The presence of heteroscedasticity does not lead to the After defining the mathematical expression to determine
estimates obtained by the least squares method being biased, the value of the deformation value in relation to the given
but causes the ratings to have no minimal variation, i.e. are load, it is necessary to note the significant influence of certain
not effective. Hence, if there is heteroscedasticity, no areas in the test zone curve. These are the minimum and
prediction based on the original model’s ratings will be maximum values that have a significant impact on the actual
effective. The variation of the forecast, apart from the model. The actual model represents the test case from which
variation of residuals, includes the variation of parameter the model base was created. This means that the impact of
estimates. Therefore, it must be ensured that the model has the accuracy error we have noted initially depends to a great
no presence of heteroscedasticity [10]. extent on these values. In Tab. 6, we see the above values that
The condition that there is no heteroscedasticity is that have a significant impact on the mathematical model
the factor p > 0.05. In Tab. 5, we see that the condition is predicting the deformation size.

182 TECHNICAL JOURNAL 13, 3(2019), 180-183

 Anđelko CRNOJA et al.: APPLICATION OF A LOGARITHMIC MODEL ON A STRESS AND DEFORMATION INTERDEPENDENCE OF THE RECYCLED AUTOMOBILE …

Table 6 Overview of the influential minimum and maximum from the model base 6 REFERENCES
Standard Residual: log log deformation (Database) Outliers
[1] European Tyre & Rubber Manufacturers’ Association. (2015).

Observed -

Predicted -

Standard -

Standard -

Std.Err. -
Residual

Residual

Pred.Val
Pred. v.
Number of End of life tyre report, http://www.etrma.org/uploads/

Value

Value
observation Modules/Documentsmanager/elt-report-v9a---final.pdf
[2] Marsili, L., Coppola, D., Bianchi, N., Maltese, S., Bianchi, M.,
& Fossi, M. C. (2014). Release of Polycyclic Aromatic
50 . . . |* . . . 0.59 0.30 0.28 -2.83 2.26 0.03
56 . . . | . * . . 1.51 1.09 0.43 -0.42 3.42 0.02
Hydrocarbons and Heavy Metals from Rubber Crump in
66 . . . * . . . 0.51 0.76 -0.25 -1.41 -2.02 0.02 Synthetic Turf Fields: Preliminary Assessment for Athletes.
89 . . . |* . . . 0.69 0.42 0.27 -2.48 2.15 0.02 Journal of Environmental and Analytical Toxicology, 5(2),
124 . .* . | . . . 0.37 0.86 -0.49 -1.12 -3.90 0.01 1000265. https://doi.org/10.4172/2161-0525.1000265
125 . . *. | . . . 0.74 1.15 -0.40 -0.23 -3.22 0.01 [3] Swedish Chemicals Inspecorate (2006). Synthetic turf from a
126 . . . * | . . . 0.91 1.25 -0.34 0.08 -2.73 0.01 chemical perspective – a status report 3/06 KEMI-
127 . . . * | . . . 1.06 1.38 -0.31 0.47 -2.50 0.01 Kemkalieinspektionen. Sundbyberg, Order. No. 510 834 July
128 . . . *| . . . 1.20 1.48 -0.28 0.79 -2.25 0.01 2006. e-mail: kemi@cm.se
129 . . . * . . . 1.28 1.54 -0.26 0.97 -2.07 0.01 [4] World Health Organization International Agency for Research
Minimum . .* . | . . . 0.37 0.30 -0.49 -2.83 -3.90 0.01
on Cancer - IARC (2010). Monographs on the Evaluation of
Maximum . . . | . * . . 1.51 1.54 0.43 0.97 3.42 0.03
Mean . . . |* . . . 0.89 1.02 -0.14 -0.62 -1.08 0.02
Carcinogenic Risks to Humans 1983. VOLUME 92 Some Non-
Median . . . *| . . . 0.83 1.12 -0.27 -0.33 -2.16 0.01 heterocyclic Polycyclic Aromatic Hydrocarbons and Some
Related Exposures, Lyon, France, 868.
[5] Simon, R. (2010). Review of the Impacts of Crumb Rubber in
Tab. 6 shows significant deviations of model values Artificial Turf Applications. UC Berkeley: Laboratory for
compared to actual measured values. As regards minimum Manufacturing and Sustainability. Retrieved from
and maximum, explanation of the occurrence is relatively https://escholarship.org/uc/item/9zp430wp
easy. We can notice that due to the nature of the test the initial [6] Birkholz, D. A., Belton, K. L., & Guidotti, T. L. (2012).
and final measurement are in the zone that is most difficult to Toxicological Evaluation for the Hazard Assessment of Tire
measure; the biggest error is in the initial deformation Crumb for Use in Public Playgrounds. Journal of the Air &
estimation and in the phase of plastic deformation or in the Waste Management Association, 53(7), 903-907.
area of material breakdown. https://doi.org/10.1080/10473289.2003.10466221
[7] Watterson, A. (2017). Artificial Turf: Contested Terrains for
The measurements were performed by a simple manual
Precautionary Public Health with Particular Reference to
stress method and the problem of recording the initial Europe? International Journal of Environmental Research and
deformation and deformation in the zone of plastic Public Health. https://doi.org/10.3390/ijerph14091050
deformation and breakdown of the material is extremely [8] http://gumiimpex.hr
difficult and subject to the subjective impression on the spot [9] HRN EN ISO 527-4:2008
at the time of measurement. [10] Nešić, N. (2014). Otkrivanje posledice prisustva
heteroskedastičnosti. Univerzitet u Novom Sadu,
5 CONCLUSION Prirodnomatematički fakultet, Departman za matematiku i
informatiku. Master rad, 90. (in Serbian)
The model is significant and shows with very high
precision the behavior of the material when it comes to the
Authors’ contacts:
stresses in real terms and the actual material that can be
obtained as a raw material on a certain geographical micro Anđelko CRNOJA, PhD student
location. Odessa State Academy of Civil Engineering and Architecture,
The accuracy of the applied multiple logarithmic model Didrihsona 4, 65029 Odessa, Ukraine
Tel: 00385992755466
is 87.21%. Therefore, we can conclude that the model is E-mail: acrnoja@hotmail.com
significant and applicable and has a very high accuracy of the
deformation estimation in relation to the applied stress. Željko KOS, PhD
The research will continue in the direction of examining Corresponding author
University North,
other properties such as the elasticity module etc. from which 31b, Jurja Krizanica, 42000 Varazdin, Croatia
information would be obtained that would be useful for Tel: 0038598757989
certain computer modelling when creating new products in a E-mail: zkos@unin.hr
wide range of human activities including civil engineering
Oleg POPOV, PhD, Assistant Professor
and construction industry. Department of Technology of Building Production,
The results obtained by applying a multiple logarithmic Odessa State Academy of Civil Engineering and Architecture,
model can be applied in defining and solving certain Didrihsona 4, 65029 Odessa, Ukraine
problems that require a response to the question of how Tel: 00380503339753
E-mail: oleg.a.popov@gmail.com
deformation is and is allowed if there is a certain stress effect.

TEHNIČKI GLASNIK 13, 3(2019), 180-183 183

ISSN 1846-6168 (Print), ISSN 1848-5588 (Online) Original scientific paper
https://doi.org/10.31803/tg-20190728144720

POWER REGULATION BY COUPLE HALF WAVE LPWM RECTIFIER AT THREE-PHASE

LOADS

Erol CAN

Abstract: The paper presents an application of power control by couple half wave LPWM rectifiers processing at the energy distribution line. The switching method with the
components of semiconductor for alternating energy control in the energy distribution line is used on alternating energy sources. In three-phase power line and load, power control
and regulation are done with the proposed modulation correction index (MCI). Therefore, the simulation model of 3-phase energy distribution is established after the relationships
between the energy sources and the circuit elements are determined by the circuit analysis method. The controls of the current and the voltage are done by trying at the different
loads in the line at the simulation. According to the modulation correction index (MCI), currents of unbalanced loads are balanced by the proposed method on the power line.
Then, the balance currents and powers that MCI provides are calculated. Finally, a power line of 15 km at length that is created by connecting the model of RLC is tested. Obtained
results show the effectiveness of the proposed method.

Keywords: balance currents; circuit analysis; modulation correction index; LPWM half rectifiers; simulation of power control

1 INTRODUCTION with making the circuit analysis of the power line. After the
design of the power line model, three-phase line operation is
As well as the production of energy, the distribution and performed in MATLAB Simulink for different load cases in
use of existing energy is of great importance. Therefore, the application phase.
many studies have been conducted on energy production and Then, obtained results of the simulation are verified in
distribution [1-3]. Direct current (DC) energy in power lines experimentation. The current and voltages of different loads
and different loads is controlled by converting it into without changing the sinus structure of current and voltage
changing energy with pulse width modulation (PWM) vary depending on the modulation index on the line. In the
inverters [4-9]. Therefore, the DC power source is derived simulation conducted for unbalanced loads, the impedance of
from either renewable energy sources or alternating current the third phase is half of the other phase impedances while
(AC) sources. The DC energy from the AC source is the two phases are equal to each other. Imbalance current of
converted back into AC current to control the power line. The the line with the low impedance value is balanced by
quality of the converted energy from the DC current regulating the modulation index value. These modulation
decreases since the current and voltage contain a high amount index values are named as modulation correction index
of harmonic distortion [10-12]. Multi-level inverters are used (MCI) for balancing the power and current values in the first
to eliminate or reduce these unwanted effects. This increases time. The imbalances due to different load conditions in the
the cost of the system and the complexity of the system while line are solved with different Modulation Correction Index
it makes it difficult to find the faults that can be on the device. values. These values are given in tables. When the results are
In addition, for some loads on the line controlled by the analyzed, the value of the voltage controlled on the load has
multi-level inverter, the quality of the current can be drawn lower distortion than that of the previous line studies with
to the desired level while the voltage of the generated energy inverters [15, 16]. In addition, these results can be obtained
cannot be obtained at the desired level [13, 14]. Thus, the in a less complicated and inexpensive way using the
paper presents a model of power control by inverse half proposed model. In addition, according to the results, the
rectifier processing method that uses the modulation power distribution line is simulated for efficient power
correction index at an energy distribution line. On the line, distribution and control without losing a lot of time and
there are two AC-source half-wave PWM rectifiers for each money. Then, the results are validated in experimentation. By
phase control current and voltage. Two GTO and two IGBT taking this model into consideration, applications can be
switches created are used on these half-wave rectifiers. This performed in less time and with less error rate. As the missing
provides a mixed switches structure at the PWM rectifiers and difficult sides of the power line in the simulation can be
while it is intended for demonstrating the availability of determined, the accidents and errors that may occur are
different accessible switch preferences when performing reduced and the loss of life and property is eliminated at the
energy control on the line. In the proposed control method, experimentation. According to the results obtained, it is
the effective values of the alternating current and voltage of observed that energy distribution and control are done
the load are controlled by PWM on the load with dividing as effectively.
the pulse width. Therefore, the modulation index values of
PWM control the effective values of the current and voltage
on the load without disturbing the sinus structures. In this
study, the structure of the proposed line model is described

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 Erol CAN: POWER REGULATION BY COUPLE HALF WAVE LPWM RECTIFIER AT THREE-PHASE LOADS

2 DESIGN OF THE PROPOSED MODEL DU m ⋅ sin(ωt + α )

I2 = (6)
ZB
At three-phase power lines, six alternating energy
sources are as Vs, four of semiconductor switches are for
every phase, one resistive load is for every phase, and parallel DU m ⋅ sin(ωt + 2α )
I3 = (7)
RL loads are connected in series to the resistive load for each ZC
phase. Four semiconductor switches used for each phase are
2-IGBT and 2-GTO at the applications. Linear Pulse Width If the B phase impedance is equal to half of the other
Modulation method (LPWM) is used to control switches phases, the operating times of the PWMs can be adjusted by
because LPWMs determine the operating time of the calculating the Modulation Correction Index (MCI) to
switches. The comparison of the triangular signals and the compensate for the current of the three phases.
direct signal to generate LPWMs is as in Fig. 1b. Fig. 1a D1 is modulation index for C phase; D2 is modulation
shows the power circuit. The power line seen in Fig. 1a index for B phase (MCI) and is calculated as shown below.
consists of three balanced phases. The accounts to be made
for a phase are valid for every phase at the line. The switches D1U m ⋅ sin(ωt + 2α ) D2U m ⋅ sin(ωt + α )
S3 and S4 provide a negative voltage of half-wave with the = (8)
ZC ZB
second Vs source on the load, while the switches S1 and S2
provide a positive voltage of half-wave with the first Vs  Z C = 2Z B 
source on the load. In this case, the sinus voltage and the   (9)
U m ⋅ sin(ωt + α ) =
U m ⋅ sin(ωt + 2α ) 
sinus current are formed by dividing according to the duty
ratio of the LPWM on the load as in Eq. (1). α is phase
difference. ωt is electrical angle as radians. D1U m ⋅ sin(ωt + 2α ) D2U m ⋅ sin(ωt + α )
= (10)
ZC 2Z C
Vs U m ⋅ sin(ωt )
= (1)
2D1 = D2 (11)
D is the duty rate at which the PWMs are used to provide
alternating sources over the load.  
The alternating voltage that occurs on the line by two  MCI= D1 − D2 
sources can be expressed as in Eq. (2).  
 D 
 MCI= D1 − 1  (12)
Vs DU m ⋅ sin(ωt )
= (2)  2 
 D1 
 MCI = 2 
The Z5 consists of a series of inductive (L) and resistive
(R) loads. The unit of R is expressed in ohm, the unit of L in
Henry, and the unit of Z6 in ohm. The modulation index of the unbalanced line according
Z6 can be expressed as in Eq. (3). to the calculated MCI value should be increased as half the
modulation index value of the C phase. The length of the
1 1 1 power distribution line shall be determined as series
= + (3)
Z6 jω L R resistance (RL), inductance (LL), capacitor (CC) loads to be
connected serially to the circuit in Fig. 1.
The ZW represents the line length impedance. ZW is
The ZA is impedance of the first phase in ohm. ZA can be
described as in Eq. (13).
expressed as in Eq. (4).

Z A = Z 6 + R1 (4) 1
Z W= jω LL + RL + (13)
jωCC
The I1 is current of the first phase in ampere. I1 can be
expressed as in Eq. (5). Impedance (ZL) of the power distribution line can be
found as in Eq. (14).
DU m ⋅ sin(ωt )
I1 = (5)
ZA Z=
L ZA + ZW (14)

The ZB is impedance of the second phase in ohm, The ZC

is impedance of the third phase in ohm. In the case of a
balanced line, for voltages that have difference as the alpha-
degree of phase, the current of the second and third phases of
the line is found as in Eq. (6) and in Eq. (7).

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 Erol CAN: POWER REGULATION BY COUPLE HALF WAVE LPWM RECTIFIER AT THREE-PHASE LOADS

a)

b)
Figure 1 a) the power line of circuit model, b) LPWM

Figure 2 Balanced power line

3 POWER LINE APPLICATION Z4 = 10 + j0.1, Vs = 220 volt, Modulation index = 0.95,

Switching frequency is 100 kHz.
The impedances of each phase are equal to each other for The circuit in Fig. 2 provides a three-phase alternating
the application in Fig. 2. Z1 = Z2 = Z3 = 10 ohm, Z6 = Z5 = voltage at 60 Hz of frequency to the power line. The voltage

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 Erol CAN: POWER REGULATION BY COUPLE HALF WAVE LPWM RECTIFIER AT THREE-PHASE LOADS

and distortion value of voltage are given in Fig. 3, while the index value. In Fig. 3b, the THD value of the voltage on the
current is as in Fig. 4. load is 4.49%. 104.7V is created with 0.95 of modulation
index on load. While the THD values of the voltage supplied
150 to the load with PWM inverters can exceed 100%, a level of
UZ5 UZ4 UZ6 4.59% can be achieved for the proposed method. In the
100 simulation, the current obtained is given at the 0.8 of
modulation index in Fig. 4.
For the balanced three-phase load that is ZA, ZB, ZC in
50
Fig. 4, a three-phase alternating current with 60° of the phase
difference is provided on load. 10.7 A is created with 0.95 of
0 modulation index on load. If loads in Fig. 2 are changed as
V

Z1 = Z3 = 10 ohm and Z2 = 5 ohm; Z5 and Z4 are 10 + j0.1,

-50 Z6 = 5 + j0.05. D is 0.8. Then, three phases are unbalanced.
Model is performed according to unbalanced loads; loads
-100
currents are shown in Fig. 5.

-150 20
0.05 0.06 0.07 0.08 0.09 0.1
t(s) 15
a) IZ5 IZ4 IZ6
10
Selected signal: 6 cycles. FFT window (in red): 2 cycles
100 5

50 0

0 A -5
V

-50 -10

-100 -15
0 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08 0.09 0.1
Time (s) -20
Fundamental (60Hz) = 104.7 , THD= 4.59%
Mag (% of Fundamental)

2 0.05 0.06 0.07 0.08 0.09 0.1

t(s)
Figure 5 Unbalanced loads of currents
1
The load at less impedance value generates more current.
0 Currents of IZ5 and IZ4 are 12 A at the maximum while
0 100 200 300 400 500 600 700 800 900 1000
Frequency (Hz) Currents of IZ6 is 24A at the maximum. The difference in
b) impedances of the loads is half. Therefore, the load with a
Figure 3 a) 3-phase alternating voltage at 60 Hz of frequency, b) distortion value of low impedance of the modulation index must be twice the
voltage
load with high impedance. Fig. 6 shows the balanced loads
15 with the effective value of their current.
IZ5 IZ4 IZ6
10 20

15
5 IZ5 IZ4 IZ6
10

0 5
A

0
A

-5
-5

-10 -10

-15
-15
0.05 0.06 0.07 0.08 0.09 0.1
-20
t(s)
Figure 4 3-phase alternating current at 60 Hz of frequency for balanced load 0.05 0.06 0.07 0.08 0.09 0.1
t(s)
For the balanced three-phase loads that are Z4, Z5, Z6 in Figure 6 The balanced loads with the effective value of their current
Fig. 3a, a three-phase alternating voltage with 60 degree of
the phase difference is provided on load. These voltages are MCI is 0.5 according to Eq. 11. Therefore, when the
formed on the load according to arranging the modulation modulation index for IZ6 is made to 0.45, the modulation

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 Erol CAN: POWER REGULATION BY COUPLE HALF WAVE LPWM RECTIFIER AT THREE-PHASE LOADS

index for IZ4 and IZ5 is 0.9. Then, IZ4 = IZ5 = IZ6 = 10.8A line imbalances. When the three-phase line is supplied with
for effective value of the current [7]. 330 volts; balancing currents and MCIs are given in Tab. 2
When the three-phase line is supplied with 220 volts; for different line imbalances. Z is 10 ohms as impedances.
balancing currents and MCIs are given in Tab. 1 for different

Table 1 Correction currents and MCIs of 3-phase lines fed with AC sources of 220V
D ZA ZB ZC MCI Imax – Ief for IZA and IZC Imax – Ief for IZB Ief f or IZA and IZC with MCI
0.8 Z 0.9Z Z 0.89 22A-17.6A 24.4A-19.6A 19.6A
0.8 Z 0.8Z Z 0.99 22A-17.6A 27.5A-22A 22A
0.7 Z 0.9Z Z 0.776 22A-15.4A 24.4A-17.08A 17.08A
0.7 Z 0.8Z Z 0.875 22A-15.4A 27.5A-19.25A 19.25A
0.7 Z 0.7Z Z 0.99 22A-15.4A 31.42A-22A 22A
0.7 Z 0.6Z Z X 22A-15.4A 36.6A-25.66A X
0.6 Z 0.9Z Z 0.666 22A-13.2A 24.4A-14.66A 14.66A
0.6 Z 0.8Z Z 0.756 22A-13.2A 27.5A-16.65A 16.65A
0.6 Z 0.7Z Z 0.857 22A-13.2A 31.42A-18.85A 18.85A
0.6 Z 0.6Z Z 0.99 22A-13.2A 36.66A-22A 22A
0.6 Z 0.5Z Z X 22A-13.2A 44A-26.4A X
0.6 Z 0.4Z Z X 22A-13.2A 55-33A X

Table 2 Correction currents and MCIs of 3-phase lines fed with AC sources of 330V
D ZA ZB ZC MCI Imax – Ief for IZA and IZC Imax – Ief for IZB Ief f or IZA and IZC with MCI
0.8 Z 0.9Z Z 0.89 33A-26.4A 36.6A-19.6A 29.4A
0.8 Z 0.8Z Z 0.99 33A-26.4A 41.25A-33A 33A
0.7 Z 0.9Z Z 0.776 33A-23.1A 36.6A-25.62A 25.62A
0.7 Z 0.8Z Z 0.875 33A-23.1A 41.25A-28.87A 28.87A
0.7 Z 0.7Z Z 0.99 33A-23.1A 47.3A-33A 33A
0.7 Z 0.6Z Z X 33A-23.1A 54.9A-38.49A X
0.6 Z 0.9Z Z 0.666 33A-19.8A 36.6A-21.99A 21.99A
0.6 Z 0.8Z Z 0.756 33A-19.8A 41.62A-24.97A 24.97A
0.6 Z 0.7Z Z 0.857 33A-19.8A 47.13A-28.27A 28.27A
0.6 Z 0.6Z Z 0.99 33A-19.8A 54.99A-33A 33A
0.6 Z 0.5Z Z X 33A-19.8A 66A-39.6A X
0.6 Z 0.4Z Z X 33A-19.8A 82.5A-44A X

Table 3 Balancing currents and balancing powers for three-phase system with 220 balanced in three cases. Although a current of 25.6 A is
volt input
required for the compensation of the line, the maximum
Impedance (Ohm) MI MCI Pb(VA) Ib(A)
0.9Z 0.8 0.89 440 2 current that the line can achieve is 22A at 0.99 of modulation
0.8Z 0.8 0.99 968 4.4 index. Current imbalance of the 6 ohm of the impedance
0.9Z 0.7 0.776 309 1.68 controlled by 0.7 modulation index cannot be compensated.
0.8Z 0.7 0.875 847 3.85 Thus, MCI is shown with X. Although a current of 26.4 A is
0.7Z 0.7 0.99 1452 6.6 required for the compensation of the line, the maximum
0.6Z 0.7 X X X
0.9Z 0.6 0.666 321,2 1.46
current that the line can achieve is 22A at 0.99 of modulation
0.8Z 0.6 0.756 759 3.45 index. Current imbalance of the 5 ohm impedance controlled
0.7Z 0.6 0.857 1243 5.65 by 0.6 modulation index cannot be compensated. So, MCI is
0.6Z 0.6 0.99 1936 8.8 shown with X for it.
0.5Z 0.6 X X X Although a current of 33 A is required for the
0.4Z 0.6 X X X
compensation of the line, the maximum current that the line
can achieve is 22 A at 0.99 of modulation index. Current
In Tab. 1, the imbalances generated in the impedances imbalance of the 4 ohm impedance controlled by 0.6
ranging from 10 ohm to 4 ohm on the line are controlled by modulation index cannot be compensated. Thus, MCI is
the modulation index that is from 0.8 to 0.6. While the shown with X for it. In Tab. 2, the imbalances generated in
effective value of the line current is balanced twice in the 0.8 the impedances ranging from 10 ohm to 4 ohm are controlled
modulation index, the effective value of the line current can on the line from 0.8 modulation index to 0.6 modulation
be set at three times for the 0.7 of modulation index value. In index. The line can be balanced in nine of twelve trials, while
the case of 0.6 modulation index, the effective value of the the line cannot be balanced in three cases. Tab. 3 shows the
line current can be compensated four times. For the 0.9Z balancing current and balancing power generated by
value of ZB at the 0.8 of the modulation index, the MCI value arranging of the MCI to compensate for the three-phase
is 0.89. For the 0.8Z value of ZB at the 0.8 of the modulation power line, which has 220V of the input voltage source. Tab.
index, the MCI value is 0.99. At the 0.7 of the modulation 4 has the balancing current and balancing power generated
index, the MCI value is 0.776 for the 0.9Z value of ZB while by arranging of the MCI to compensate for the three-phase
the MCI value is 0.875 for the 0.8Z value of ZB. The line can power line, which has 330V of the input voltage source. The
be balanced in nine of twelve trials, while the line cannot be balance current (Ib) is the difference between the high phase

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 Erol CAN: POWER REGULATION BY COUPLE HALF WAVE LPWM RECTIFIER AT THREE-PHASE LOADS

current and the low phase current values. This value can be impedance value (Z) is 10 ohm, the balancing current and
expressed as follows. power cannot be provided with 0.6 of modulation index to
the system supplied with 220 volts for 0.5Z and 0.4Z
I b I ZA − I ZB
= (14) impedance values. When the impedance value (Z) is 10 ohm,
the balancing current and power cannot be provided with 0.7
I b I ZA − I ZB
= (15) of modulation index to the system supplied with 220 V for
0.6Z of the impedance values.
The balance power (Pb) can be found as in Eq. (16) while Table 4 Balancing currents and balancing powers for three-phase system with 330
Ui is input voltage for the line. volt input
Impedance (Ohm) MI MCI Pb(VA) Ib(A)
P= Ui ⋅ Ib (16) 0.9Z 0.8 0.89 880 4
b 0.8Z 0.8 0.99 1936 8.8
0.9Z 0.7 0.776 618 336
For the impedance of 0.9Z at Tab. 2, a compensation 0.8Z 0.7 0.875 847 7.7
power of 440 VA and a balancing current of 2 A are provided 0.7Z 0.7 0.99 2904 13.2
with a 0.89 MCI value when a compensation power of 0.6Z 0.7 X X X
0.9Z 0.6 0.666 642 2.92
968VA and a balancing current of 4.4 A are provided with a 0.8Z 0.6 0.756 1518 6.9
0.99 of MCI. The first greatest balancing power and current 0.7Z 0.6 0.857 2486 11.3
are 1936 VA and 8A that are provided with 0.99 of MCI at 0.6Z 0.6 0.99 3872 17.6
the 0.6Z of impedance, while the second greatest balancing 0.5Z 0.6 X X X
power and current are 1452 VA and 6.6 A that are provided 0.4Z 0.6 X X X
with 0.99 of MCI at 0.7Z of the impedance. When the

Figure 7 Regulated power line of 15 km

For the impedance of 0.9Z at Tab. 4, a compensation with 0.99 of MCI at the 0.6Z of impedance, while the second
power of 880 VA and a balancing current of 4 A are greatest balancing power and current are 2904 VA and 13.2
provided with a 0.89 MCI value when a compensation A that are provided with 0.99 of MCI at 0.7Z of the
power of 968VA and a balancing current of 8.8 A are impedance. As the unbalanced phase impedance decreases,
provided with a 0.99 of MCI. The first greatest balancing the applied MCI and the balancing current increase, which
power and current are 3872 VA and 8 A that are provided leads to an increase in the balancing power. When the

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 Erol CAN: POWER REGULATION BY COUPLE HALF WAVE LPWM RECTIFIER AT THREE-PHASE LOADS

impedance value (Z) is 10 ohm, the balancing current and Parallel RL loads connected in series at the beginning and
power cannot be provided with 0.6 of modulation index to end of the 15 km long line are energized with alternating
the system supplied with 330 V for 0.5Z and 0.4Z source, a three-phase alternating current that occurs on the
impedance values. In line with the model in Figure 1, a line load is presented in Fig. 9.
length of 15 km in Fig. 7 can be obtained if a serial RLC
circuit is added to the series. Z1 = Z2 = Z3 = Z4 = Z5 = Z6 15

= 10 + j0.1. IZ5 IZ4 IZ6

R, L, C values for the impedance of the line (Zw) are 10

respectively as 0.143 ohm, 102×10−2 H, C = 1510×10−8.

Regulated power line of 15 km is in Fig. 7. 5
Parallel RL loads connected in series at the beginning
and end of the 15 km long line in Fig. 7 are energized by 0
alternating power sources that are controlled by switches

A
with 0.9 of modulation index. The three-phase alternating -5
voltage that occurs at the end of the power line is as in Fig.
8a, while the harmonic distortion of the voltage on the load -10
is as in Fig. 8b.
-15
0.05 0.06 0.07 0.08 0.09 0.1
150 t(s)
UZ5 UZ4 UZ6 Figure 9 A three-phase alternating current of the 15 km long line
100
On the power line, a 12-volt alternating current at the
50 maximum value is formed on loads. The effective value of
the voltage is 10.2 A because the modulation index is 0.9.
According to the results, the power distribution line is
0
V

simulated for efficient power distribution and control

without losing a lot of time and money. By taking this model
-50
into consideration, applications can be performed in less
time and with less error rate. As the missing and difficult
-100 sides of the power line in the simulation can be determined,
the accidents and errors that may occur are reduced, and the
-150
0.05 0.06 0.07 0.08 0.09 0.1
loss of life and property is eliminated.
t(s)
a) 4 CONCLUSION
Fundamental (50Hz) = 101.3 , THD= 16.04%
The paper presented power control by inverse half
20 rectifier processing method at energy distribution line in the
simulation. The three-phase power line was controlled by
Mag (% of Fundamental)

15 semiconductor switches in reverse and parallel connected

sources for each phase. First, the circuit model and
mathematical equations of the line were created. In
10 mathematical equations, the effect of the modulation index
of the control signals applied to the switches to the power
occurring on the load was shown. In unbalanced loads, it
5
was shown how to calculate the values of MCI to equalize
the effective value of the current. The current and voltage of
0 the line were measured at different loads in the line. The
0 100 200 300 400 500 600 700 800 900 1000
Frequency (Hz) balancing current and power were calculated by measuring
b) for different modulation indices and line impedances.
Figure 8 a) The three-phase alternating voltage that occurs at the end of the line, Obtained results and the effect of modulation index on the
b) the harmonic distortion of the voltage on the load
results were discussed. Unbalanced load current imbalances
were eliminated by equalizing the effective values of the
On the power line, 101 volts of the alternating voltage
currents. As the unbalanced phase impedance decreases, the
at the maximum value is formed on loads. The effective
applied MCI and the balancing current increase, which leads
value of the voltage is 90.9 V because the modulation index
to an increase in the balancing power. According to the
is 0.9. Although there is no filtering element on the line, the
results obtained, the design and application of the line has
distortion of the load voltage is 16%. If the load on such a
been successfully achieved.
line is provided with alternating voltage by conventional
inverter methods, this value will exceed 100%. When

190 TECHNICAL JOURNAL 13, 3(2019), 184-191

 Erol CAN: POWER REGULATION BY COUPLE HALF WAVE LPWM RECTIFIER AT THREE-PHASE LOADS

5 REFERENCES [15] Raj, N., Jagadanand, G., & George, S. (2016). A Modified
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https://doi.org/10.1016/j.solener.2017.11.039 M. (2015). Wavelet PWM Technique for Single-Phase Three-
[2] Niu, B., Hwangbo, H., Zeng, L., & Ding, Y. (2018). Level Inverters. Journal of Power Electronics, 15(6), 1517-
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[5] Ananda, A. S. (2018). Performance Analysis of Series-Passive
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Energy Management (pp. 139-146). Springer, Singapore.
https://doi.org/10.1007/978-981-10-4394-9_14
[6] Kumar, M. (2018). Time-Domain Characterization of
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[7] Mukherjee, S., Giri, S. K., Kundu, S., & Banerjee, S. (2018).
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NPC Traction Inverter with Minimum Switching Loss for
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Applications. https://doi.org/10.1109/TIA.2018.2866565
[8] Takahashi, H., Obara, H., & Fujimoto, Y. (2018, March).
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(AMC), 2018 IEEE 15th International Workshop on (pp. 229-
233). IEEE. https://doi.org/10.1109/AMC.2019.8371093
[9] Sivakumar, P., & Arutchelvi, M. S. (2018). Modified
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[12] Can, E. (2018). The modeling and analysis of a power
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TEHNIČKI GLASNIK 13, 3(2019), 184-191 191

ISSN 1846-6168 (Print), ISSN 1848-5588 (Online) Original scientific paper
https://doi.org/10.31803/tg-20190211142404

INFLUENCE OF AN UNEVEN SURFACE ON THE VIBRATION OCCURRENCE AFFECTING THE

TRACTOR OPERATOR

Željko BARAČ, Ivan PLAŠČAK, Tomislav JURIĆ, Pavo BALIČEVIĆ, Vinko DUVNJAK, Mladen JURIŠIĆ, Goran HEFFER,
Monika MARKOVIĆ

Abstract: The paper presents a study of the influence of an uneven surface and number of tractor hours on vibration that is transmitted to the operator's hand-arm system during
operation. The study was conducted on the asphalt, gravel and grass traversal during 2015 and 2016. The results indicate that the movement of a tractor on different agrotechnical
surfaces generates vibrations of varying intensity that affect the hand-arm system of the operator. The highest vibration values were recorded on the asphalt, while the least
vibrations were measured on the grass. The measured maximum vibration values are lower than the permissible 5 m·s−2 in the direction of all three axes, making it possible to
assume that they are not harmful to the health of the operator.

Keywords: agrotechnical surfaces; hand-arm system; vibration

1 INTRODUCTION Authors [6] point out that cardiovascular disorders result

from vibration exposure in which case operators often
There are numerous negative effects of vibration on the complain about occasional pain in hands or white fingers,
operator. However, since vibration is closely intertwined which is a sign of hypothermia. Neurological disorders occur
with other occupational hazards, a clear causal link between when hands and arms are exposed to vibration causing
the impact of vibration and health damage cannot be tingling and numbness of the hand or the whole arm. A
established. A wealth of research shows that constant short- muscle and the peripheral nervous system disorder affecting
term exposure to high vibration can cause stomach and chest the hand or arm is a consequence of vibration exposure that
pain, lack of air, nausea and dizziness, whereas constant produces irreversible changes in hand bones and wrist joints.
long-term exposure can result in psychomotor, physiological, Workers exposed to long-term vibration generally complain
and psychological disorders [1]. The structure of an of muscle weakness and tingling in hands and arms.
agricultural tractor consists of a fixed connection between the Additionally, vibration decreases the firmness of grip
axes and the tractor, which is especially unfavorable strength, which is considered a direct consequence of
regarding the transmission of mechanical vibration to the mechanical damage to peripheral nerves. Cardinale and
operator’s workplace. Mechanical vibration is transmitted Wakeling [7] argue that constant exposure to high vibration
through the operator's seat, the floor of tractor cabs, steering frequencies can significantly impair one's health. The
wheels, control and driving levers. The negative impact of operator’s hand-arm system is the most susceptible to
mechanical vibration decreases the operator’s concentration vibration within the frequency range of 6-16 Hz [8, 9, 10].
affecting his/her central nervous system and potentially Fahy and Thompson [11] point out that the transfer of
causing occupational diseases of the spine and stomach [1, vibration to the operator's body occurs when the body is
2]. Vibration is an oscillatory body movement which can be leaning against a vibrating surface (e.g. when in a seated
straight or angular depending on the motion path. The position on a vibrating chair; in a standing position on a
increase in speed of agrotechnical practices has created new vibrating floor; in a lying position on a vibrating surface).
problems relating to the dynamic behavior of machinery and Bogadi-Šare [12] claims that the operator exposed to general
exposure of the operator’s body to vibration. An increased vibrations can develop osteoarticular diseases. The changes
speed of agrotechnical practices intensifies mechanical in the lumbar vertebrae in 90 % of the general population
vibration, which consequently affects the operator [3]. aged between 55 and 60 can be confirmed by x-ray, whereas
Electrical and pneumatic hand-held tools can cause the same can be confirmed among 100 % of the vibration-
hand-arm vibration [4]. Depending on the intensity, exposed population aged between 45 and 50. Zeng [13]
frequency, and exposure period, the changes can be claims that constant vibration exposure accompanied by the
temporary (i.e. reversible) or permanent. Working in a cold aging of the agricultural population presents a significant risk
environment increases injury risk. When exposed to to their health. Therefore, a modification of vehicle design
vibration, it is necessary to avoid hand hypothermia (e.g. should facilitate a decrease in vibration created by
keep the hands warm using gloves or a source of heat). agrotechnical practices. Pobedin et al. [14] point out that
Furthermore, it is necessary to measure vibration in an vibration reduction can be achieved by adding a vibration
objective way to determine the real danger to human health, muffler into the tractor cab. Authors [15] claim that modern
as well as to develop mechanisms and equipment to protect tractors are often equipped with parts that reduce the
the operator from the negative impact of vibration [5].

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 Željko BARAČ et al.: INFLUENCE OF AN UNEVEN SURFACE ON THE VIBRATION OCCURRENCE AFFECTING THE TRACTOR OPERATOR

vibration transferred to the driver (e.g. low-pressure tyres, air 3 RESULTS AND DISCUSSION
sprung seat and cab, and front axle suspension).
Barač et al. [16] measured the vibration that affects the Compared to the results obtained in 2015, the results for
operator's hand-arm system when working with a sprayer and 2016 show a slight vibration deviation in the direction of all
mulcher. The lowest vibration values were measured on a three axes measured on all three types of surfaces (gravel,
sprayer in the direction of the x, y and z axes. Barač et al. [17] asphalt, and grass surface) (Tab. 1).
researched the impact of various agrotechnical surfaces
Table 1 Mean values (m·s−2)
(asphalt, gravel and grass surface) on the level of vibration
x axis y axis z axis
that affect the hand-arm system. The results show that the Surfaces Year
lowest vibration values were obtained for the grass surface in 2015 2016 2015 2016 2015 2016
the direction of all axes, whereas the highest values were Asphalt 0.079 0.081 0.071 0.073 0.069 0.071
obtained on the asphalt and gravel surfaces in the direction of Gravel 0.060 0.063 0.071 0.074 0.037 0.070
x and y axes, and the y axis, respectively. Grass 0.020 0.023 0.069 0.073 0.040 0.044
The aim of the research is to establish the level of
The highest mean vibration values were measured in the
mechanical vibration that affects the operator’s hand-arm
direction of x and z axes on the asphalt surface in 2015 and
system on various agrotechnical surfaces in relation to an
2016. The highest mean vibration values in 2015 were
increased amount of the tractor’s work hours. It is expected
obtained in the direction of the y axis on the asphalt and
that the increase in work hours will result in a heightened
gravel road, while the highest mean values were measured on
level of vibration that affects the hand-arm system of the
the gravel road in 2016. The lowest vibration values in the
driver of an agricultural tractor.
direction of the x axis were measured as follows: in 2015 and
2016 when the tractor moved along a grass surface; in 2015
2 MATERIALS AND METHODS
in the direction of the y axis along a grass surface; in 2016 on
the asphalt and grass surface in the direction of the z axis; in
The research was performed on a Landini Powerfarm
2015 on the gravel road; in 2016 on the grass surface.
100 tractor through a two-year period. Over the first and
Comparable results were obtained by the authors [23],
second research year (2015 and 2016), the tractor reached 5
who measured the vibrations produced by framesaws and
800 and 6 800 hours of work, respectively. The
bandsaws. The authors established that the obtained vibration
measurements were conducted on the agricultural fields and
level does not carry any health risk to the operator positioned
access roads of the School of Agriculture and Veterinary
on the framesaw stand even after an eight-hour exposure
Medicine in Osijek to establish the values of vibration
period. However, a one-hour exposure results in decreased
influencing the hand-arm system of the operator (in the
working conditions, which can afflict workers' wellbeing and
direction of the x, y and z axes). The tractor moved along
their efficiency. Deboli et al. [24] measured the vibrations on
gravel, asphalt, and grass surfaces. The measurement of
four tractors equipped with several types of tyres on three
vibration was repeated three times, which produced the
different surfaces, i.e. gravel road, asphalt, and a combination
mean value of vibration used for further research. Each
between asphalt and gravel road. In the last case, two tyres
measurement lasted for 30 minutes.
drove along the gravel road, and the other two along the
Vibration level measurement was performed in
asphalt road. Irrespective of the tyre type, the lowest
accordance with the standards [18, 19, 20], which define the
vibration was obtained when the tractor moved along the
limits of vibration exposure, their effects on the operator's
asphalt surface. The vibration level in this case did not reach
health, and include the guidelines for measurements at the
the allowed limit values, which is in accordance with the
workplace. The measurements were performed with a
results of our research. The results of the descriptive statistics
measuring device MMF VM30. A sensor was mounted on
related to the mean values of the obtained vibration in the
the steering wheel with the coordinates set in the direction
direction of the x and z axes on the asphalt surface (Tab. 2)
[20]: x axis: longitudinally (along the axis of motion –
show that the standard error was higher in the second year of
forward (positive) / backward (negative); y axis: laterally
measurement (2) compared to the first year (1), whereas it
(at the right angle to the motion direction); and z axis:
remained the same in the direction of the y axis for both
vertically, upward (positive) / downward, vertically to the
years. Furthermore, the variance analysis of the mean values
surface (negative). The weather conditions in 2015 were as
for the obtained vibration impacting the hand-arm system of
follows: air temperature ranged between 29° C and 31 °C;
the driver in the direction of all three axes (x, y and z) on the
relative humidity ranged from 62 % to 64 %; the impact of
asphalt surface shows no statistically significant difference
wind was minimal. The weather conditions in 2016 were
between the measurements in both the first and second year.
similar.
Tab. 3 shows the descriptive statistics related to the mean
The directives [21] and OG [22] contain both the limit
values of the obtained vibration in the direction of x and y
values and critical values for the exposure of the hand and
axes on the gravel surface. It is discernible that a higher
arm and they are as follows:
standard error occurs in the second (2) year of measurement
• The limit value for daily exposure based on the reference
compared with the first year (1). Variance analysis of the
time of eight hours is 5 m·s−2;
mean values of vibration in the direction of the x, y and z axes
• The critical value for daily exposure based on the
on the gravel surface shows no statistically significant
reference time of eight hours is 2.5 m·s−2.

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 Željko BARAČ et al.: INFLUENCE OF AN UNEVEN SURFACE ON THE VIBRATION OCCURRENCE AFFECTING THE TRACTOR OPERATOR

difference concerning the mean value of the obtained determined in the first (1) measurement year. The variance
vibration in both the first and second measurement year. analysis of the mean values of vibration in the direction of
The highest standard error related to the obtained the x, y and z axes on grass impacting the hand-arm system
vibration was measured in the direction of the x and z axes on did not reveal any statistically significant differences
the grass surface in the second (2) measurement year (Tab. between the first (1) and second (2) measurement year.
4). A higher standard error in the direction of the y axis was

Table 2 Descriptive statistics and variance analysis for occurred vibrations on asphalt surface
N x σ C.V. (%) st. error F Sig. (95 %)
x axis
2015 3 0.07967 0.004509 5.65 0.002603
2016 3 0.08100 0.004583 5.65 0.002646 0.129 0.738
Total 6 0.08033 0.004131 5.14 0.001687
y axis
2015 3 0.07133 0.006110 8.56 0.003528
2016 3 0.07333 0.006110 8.33 0.003528 0.161 0.709
Total 6 0.07233 0.005574 7.70 0.002275
z axis
2015 3 0.06900 0.005568 8.06 0.003215
2016 3 0.07133 0.006028 8.45 0.003480 0.243 0.648
Total 6 0.07017 0.005345 7.61 0.002182

Table 3 Descriptive statistics and variance analysis for occurred vibrations on gravel surface
N x σ C.V. (%) st. error F Sig. (95 %)
x axis
2015 3 0.06033 0.002517 4.17 0.001453
2016 3 0.06300 0.003000 4.76 0.001732 1.391 0.304
Total 6 0.06167 0.002875 4.66 0.001174
y axis
2015 3 0.07100 0.004583 6.45 0.002646
2016 3 0.07400 0.005568 7.52 0.003215 0.519 0.511
Total 6 0.07250 0.004848 6.68 0.001979
z axis
2015 3 0.03667 0.032146 87.66 0.018559
2016 3 0.07000 0.020000 28.57 0.011547 2.326 0.202
Total 6 0.05333 0.030111 56.46 0.012293

Table 4 Descriptive statistics and variance analysis for occurred vibrations on grass surface
N x σ C.V. (%) st. error F Sig. (95 %)
x axis
2015 3 0.02067 0.003055 14.77 0.001764
2016 3 0.02333 0.003512 15.05 0.002028 0.985 0.377
Total 6 0.02200 0.003286 14.93 0.001342
y axis
2015 3 0.06900 0.006557 9.50 0.003786
2016 3 0.07333 0.005508 7.51 0.003180 0.768 0.430
Total 6 0.07117 0.005913 8.30 0.002414
z axis
2015 3 0.04000 0.002000 5 0.001155
2016 3 0.04400 0.004583 10.41 0.002646 1.920 0.238
Total 6 0.04200 0.003847 9.15 0.001571

4 CONCLUSION asphalt and gravel surfaces in 2015, and for the gravel surface
in 2016;
The following conclusions can be drawn based on our - The lowest vibration levels were obtained as follows: for
two-year research: the grass surface in the direction of the x axis in 2015 and
- The level of vibration that impacts the hand-arm system 2016; in the direction of the y axis in 2015; in the direction
for all agrotechnical surfaces in the direction of the x, y and z of the z axis in 2016. The lowest level for the asphalt surface
axes was higher in the second (2) measurement year was obtained in the direction of the y axis in 2016 (the same
compared to the first (1) measurement year, which is in result was obtained for the grass surface). The lowest level
accordance with the specified hypothesis; for the gravel surface was obtained in the direction of the z
- The highest levels of vibration were obtained for the axis in 2015;
asphalt surface in the direction of the x and z axes (in 2015 - The research shows that different agrotechnical surfaces
and 2016), as well as in the direction of the y axis for the (i.e. asphalt, gravel and grass surfaces) produce vibration of
various intensity levels that are transmitted to the hand-arm

194 TECHNICAL JOURNAL 13, 3(2019), 192-196

 Željko BARAČ et al.: INFLUENCE OF AN UNEVEN SURFACE ON THE VIBRATION OCCURRENCE AFFECTING THE TRACTOR OPERATOR

system of the agricultural tractor operator. Irrespective of the from https://hrcak.srce.hr/index.php?show=clanak&id_clanak

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45-49. https://doi.org/10.1016/S0003-6870(02)00076-5 The relationship of agrotechnical interventions on the level of
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https://hrcak.srce.hr/112849 Scientific/Professional Conference Agriculture in Nature and
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283-289. Retrieved from human exposure to whole-body vibration – Part 1: General
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measuring and evaluation whole body and hand-arm evaluation of human exposure to hand-transmitted vibration –
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359. framesaws and bandsaws. Scientific journal of wood
[11] Fahy, F. & Thompson, D. (2015). Fundamentals of Sound and technology, 58(1), 19-22. Retrieved from
Vibration, Second Edition. University textbook, Institute of https://hrcak.srce.hr/index.php?show=clanak&id_clanak_jezi
Sound and Vibration Research, University of Southampton, k=19667
Southampton. Retrieved from https://books.google.hr/ [24] Deboli, R., Calvo, A., Preti, C., Palietto, G. (2008). Whole
books?hl=hr&lr=&id=znd3CAAAQBAJ&oi=fnd&pg=PP1& body vibration (wbv) transmitted to the operator by tractors
dq=11.%09Fahy,+F.,+Thompson,+D.+Fundamentals+of+Sou equipped with radial tires. International conference Innovation
nd+and+Vibration,+Second+Edition.+Institute+of+Sound+an Technology to Empower Safety, Health and Welfare in
d+Vibration+Research,+University+of+Southampton,+South Agriculture and Agro-food Systems, Ragusa, 1-10.
ampton,+2015.&ots=BP1zI0Wbpa&sig=HSHPF7daxNGN6G Retrieved from http://www.ragusashwa.it/CD_2008/lavori/
M-XRd_gKP3U6I&redir_esc=y#v=onepage&q&f=false TOPIC7/poster/DEBOLI-1.pdf
[12] Bogadi-Šare, A. (1993). Whole body vibration syndrome – a
medical problem requiring more attention. Archives of
Industrial Hygiene and Toxicology, 44(3), 269-279. Retrieved

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 Željko BARAČ et al.: INFLUENCE OF AN UNEVEN SURFACE ON THE VIBRATION OCCURRENCE AFFECTING THE TRACTOR OPERATOR

Authors’ contacts:

Željko BARAČ, MSc, Research Assistant

Corresponding author
Faculty of Agrobiotechnical Sciences Osijek,
Vladimira Preloga 1, 31000 Osijek, Croatia
zbarac@fazos.hr

Ivan PLAŠČAK, PhD, Associate Professor

Faculty of Agrobiotechnical Sciences Osijek,
Vladimira Preloga 1, 31000 Osijek, Croatia
iplascak@fazos.hr

Tomislav JURIĆ, PhD, Full Professor

Faculty of Agrobiotechnical Sciences Osijek,
Vladimira Preloga 1, 31000 Osijek, Croatia
tjuric@fazos.hr

Pavo BALIČEVIĆ, PhD, Full Professor

Faculty of Agrobiotechnical Sciences Osijek,
Vladimira Preloga 1, 31000 Osijek, Croatia
pbalicevic@fazos.hr

Vinko DUVNJAK, PhD, Scientific Adviser

Agricultural Institute Osijek,
Južno predgrađe 17, 31000 Osijek, Croatia
vinko.duvnjak@poljinos.hr

Mladen JURIŠIĆ, PhD, Full Professor

Faculty of Agrobiotechnical Sciences Osijek,
Vladimira Preloga 1, 31000 Osijek, Croatia
mjurisic@pfos.hr

Goran HEFFER, PhD, Full Professor

Faculty of Agrobiotechnical Sciences Osijek,
Vladimira Preloga 1, 31000 Osijek, Croatia
hgoran@fazos.hr

Monika MARKOVIĆ, PhD, Assistant Professor

Faculty of Agrobiotechnical Sciences Osijek,
Vladimira Preloga 1, 31000 Osijek, Croatia
mmarkovic@fazos.hr

196 TECHNICAL JOURNAL 13, 3(2019), 192-196

ISSN 1846-6168 (Print), ISSN 1848-5588 (Online) Original scientific paper
https://doi.org/10.31803/tg-20190226095826

THE EFFECTS OF DIELECTRIC VALUES, BREAST AND TUMOR SIZE ON THE DETECTION OF
BREAST TUMOR

Nuşin UNCU, Emine AVŞAR AYDIN

Abstract: Although breast cancer is the second main cause of female deaths after lung cancer, early diagnosis plays a crucial role to diminish the death rate. Many techniques
have been improved to detect the cancerous cells. At different microwave frequencies, the malignant cells indicate different electrical characteristics as compared to the normal
cells. According to these frequencies, the breast tissue is more permeable than other tissues such as the brain and muscle. Due to this property of the breast tissue, microwaves
can be used for the detection of breast cancer. In this study, the breast prototype was modelled using the CST STUDIO SUITE electromagnetic simulation software with respect
to different breast size, tumor size and dielectric values tested at a range of the 0-3.0 GHz frequency. The objective of this paper is to investigate the effects of each factor and the
interactions of factors on detecting cancer cells using the factorial analysis. The results indicate that the factors such as fat and skin permittivity, tumor and breast sizes are more
effective in the detection of breast tumor. Although the effect of fibro permittivity is not significant alone, there are considerable interaction effects of a large breast size and small
tumor size through low-to-high values of fibro permittivity. Furthermore, the combinations of a breast radius smaller than almost 8.5 cm with a high level tumor radius and breast
radius larger than 8.5 cm with a low level tumor radius are desirable for lessening the return loss value.

Keywords: dielectric properties; factorial design; factor effects; microwave breast cancer detection

1 INTRODUCTION The thermal phenomena of conduction, convection and

radiation play only a secondary role in temperature
Breast cancer is one of the main reasons of female death equilibrium, when an object is exposed to microwaves. The
worldwide [1-5]. It is a key factor that the tumor be reason for this is that the release of heat is so instantaneous.
recognized in the early stages for a higher survival rate. In In a research study, the data from 15 patients showed that
the last decade, the Microwave Imaging System [6-10] has the values of dielectric properties for malignant breast tissues
been the focus of many researchers because of some at 1-2 GHz are 3-5 times higher than the normal breast tissues
drawbacks of the existing breast cancer detection techniques [1]. In another study, 12 measurements indicated that
which are the magnetic resonance imaging (MRI), X-ray dielectric properties of malignant breast tissues are roundly
mammography, and ultrasound. Among these breast cancer 10 times greater than the normal breast tissues since
imaging techniques, the MRI cost is very high and it also only malignant tissues have a lot of water and are also more active
has the advantage of screening evaluation before surgical in relation to the normal tissues.
operation. The X-ray mammography has hazardous Malignant tumors have higher relative permittivity and
radiation, false positives and painful breast compression. The conductivity values than the normal breast tissue. These
microwave-based breast cancer imaging is one of the most values can be as high as 10 times for adipose fat, but drop to
promising methods for detecting breast cancer during its a contrast of around 10%, mainly in conductivity, for fibro
early development. This method relies on the differences in glandular (FG) tissue. This contrast has posed a challenge for
the dielectric properties of benign and malignant breast the microwave imaging community as FG tissue is where
tissues which are skin, fat, fibro glandular, tumor [1, 2]. most breast tumors originate [12]. Understanding the
Dielectric properties of a material are obtained by mechanisms that result in the high permittivity and hyper-
measuring its ability to interact with electromagnetic energy conductivity of tumors is therefore a crucial part of breast
[11]. The electric and magnetic forces generated by cancer imaging. There have been many factors with
electromagnetic (EM) fields can cause changes in the difference in dielectric properties between the normal and
interaction results. In addition to that, these properties tell us malignant tissues.
a lot about the mechanism of interaction of electromagnetic One of factors is necrosis [13]. It is usually found in
fields with various biological systems, including malignant breast tissue. Necrosis leads to the breakdown of
biopolymers, membranes and cells. cell membranes and thus a larger fraction of tissue can carry
An EM field primarily acts upon components within the current at low frequencies, which decreases the capacitance
materials in biological tissues. These materials have a net of the tumor.
electric charge and/or electric dipole moment. The main The second factor is the charging of the cell membrane
source of electric dipole moments in tissues belongs to polar [13]. In breast carcinoma, fat lobules are replaced with
molecules. The other additional sources are protein fibroblastic proliferation and epithelial cells are accompanied
structures, muscles, fat, etc. Due to the fact that the electrical by a variety of alterations at the transformed cell surface.
properties of a tissue are determined by such a wide variety Cancer cell membranes have a reduced potential and have the
of components, as reflected in different dielectric ability to absorb positive ions because they have a higher
dispersions, these properties exhibit significant variations. negative surface charge. As a result, the conductivity of the

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 Nuşin UNCU, Emine AVŞAR AYDIN: THE EFFECTS OF DIELECTRIC VALUES, BREAST AND TUMOR SIZE ON THE DETECTION OF BREAST TUMOR

malignant tissue is increased because of the displacement and Design of Experiment (DOE) techniques have been used
rotations of this mobile charge by the microwave field. extensively in many different scientific fields. These
The relaxation times which are a third factor in malignant techniques are beneficial for getting accurate statistical
tissues are larger than those in the normal tissues resulting inferences for revealing the effects of factors on a process
from the increased motional freedom of water [13]. The last with less experimenting rather than considering all the
one is sodium concentration and water content [13]. The combinations of factors. One of the DOE technique
sodium concentration in cancer cells is higher than that in applications is found in [16] for analytical chemistry. In
normal cells. The high sodium concentration alone yields another study [17], a considerable decrease of patient
higher permittivity and conductivity values for malignant dissatisfaction was given for the emergency room. [18]
tissue. This higher sodium concentration also affects the cell applied the factorial design technique to see the effects of
membrane potential and causes the malignant tissue to retain prophylactic antiemetic interventions on the risk of
more fluid. This retained fluid is in the form of bound water, postoperative nausea and vomiting of the surgery patients.
which has higher permittivity and conductivity values. Another case study on the effect of treatment factors on the
Malignant tissue therefore has a higher water content ratio quality of life of patients with breast cancer is found in [19].
than that of normal tissue, which coincides with higher values In this study, 2k factorial design is used to reveal the effects
of permittivity and conductivity than normal breast tissue at of factors and their interactions on the success of detecting
the same microwave frequency. breast tumor.
The understanding and development of medical The outline of the paper starts with the introduction
microwave techniques needs knowledge of the microwave section. It is followed by illustrating the factors considered in
dielectric properties of human tissues. There have been many breast cancer detection and applying simulation and the
data on the dielectric properties of female human general factorial design. In the third section, significant
normal/malignant/benign and surrounding breast tissue. effects of factors and their interaction graphs are given.
Dielectric properties of breast carcinoma and the Finally, further suggestions on the improvement of breast
surrounding tissues were measured [14]. The experiments cancer detection are explained in the conclusion part.
were performed at the frequencies from 100 kHz to 100 MHz
at 37 °C using an automatic network analyzer and an end-of- Table 1 Computer fitted dielectric parameters of breast carcınoma and the
surrounding tissues in the frequency range from 100 kHz to 100 MHz [14]
the-line capacitive sensor. Using a computer program, the
Specimen Sample σDC
cole-cole parameters were found by curve fitting. Tissues Location No.
εδ ε∞ τ (μs) α
(ms/cm)
Diagnosis
were divided into three main categories. These were the 1 6090 50 0.633 0.326 2.20
central part of the tumor, the tumor surrounding tissue, and 2 8260 50 0.595 0.311 3.03 Infiltrating
the peripheral tissue. Tumor specimens were taken from 3 3720 50 0.267 0.283 6.47 ductal
A
4 5170 50 0.288 0.239 6.91 carcinoma
seven different patients. From each specimen, depending on 5 3440 50 0.238 0.238 7.12 metastases
its size, 2-6 samples in the form of thin disks were excised. 6 5710 50 0.263 0.277 6.60
The number of samples was 28. The duration of all Infiltrating
1 3330 50 1.30 0.380 3.3
measurements was 4 h after the surgery. As seen from Table B
2 5510 30 0.33 0.250 5.70
ductal
1, measurements showed significant differences in dielectric carcinoma
1 793 20 0.579 0.232 0.82 Infiltrating
properties between the samples taken from different C 2 482 30 0.603 0.281 0.38 ductal
locations. Surgical pathology reported the following 3 3310 30 0.557 0.310 3.05 carcinoma
diagnoses: A-infiltrating ductal carcinoma without 1 2740 30 0.269 0.358 3.89
Infiltrating
metastases, B-infiltrating ductal carcinoma, C-infiltrating 2 3285 30 0.3202 0.275 5.75
D lobular
3 2320 30 0.259 0.278 6.49
ductal carcinoma with focal papillary component, D- 4 1253 319 0.670 0.400 3.52
carcinoma
infiltrating carcinoma consistent with lobular carcinoma, E- 1 3125 167 0.525 0.223 1.02
Infiltrating
infiltrating lobular carcinoma, F-infiltrating ductal E
2 7060 30 1.605 0.362 4.99
lobular
carcinoma, G-infiltrating lobular carcinoma. 3 13100 30 1.396 0.349 6.59
carcinoma
4 3080 50 0.45 0.298 3.90
Using a resonant cavity technique, complex permittivity 1 8830 30 1.408 0.360 2.78 Infiltrating
of in vitro diseased and non-diseased human female breast F 2 10170 30 1.210 0.340 2.73 ductal
tissues were measured at 3.2 GHz [15]. Both dielectric 3 180 10 0.684 0.149 0.120 carcinoma
properties and water contents of these tissues were found. 1 288 10 0.983 0.10 0.161
Experimental data were compared with the models predicted 2 298 10 1.008 0.075 0.130
Infiltrating
3 675 10 1.391 0.163 0.444
from mixture equations. G
4 7930 50 1.216 0.367 5.33
lobular
Hitherto, breast cancer detection studies were carried out carcinoma
5 5490 50 0.768 0.379 4.15
using dielectric properties; however the effect of dielectric 6 8660 50 1.415 0.331 5.16
properties has not been investigated. A 3D-breast was
modeled by using the CST STUDIO SUITE electromagnetic 2 SIMULATION MODEL OF BREAST TUMOR
simulation software and analyzed by using different
dielectric properties and different breast and tumor sizes A hemisphere breast model was designed as showed in
based on experimental design analyses results in the Fig. 1 according to the dielectric properties of tissues which
frequency range from 0 GHz to 3 GHz. are permittivity (ε) and conductivity (σ). Microwave imaging
was carried out by transmitting a sequence of

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 Nuşin UNCU, Emine AVŞAR AYDIN: THE EFFECTS OF DIELECTRIC VALUES, BREAST AND TUMOR SIZE ON THE DETECTION OF BREAST TUMOR

electromagnetic waves through the breast model and factors A, C, J and K are less than 0.05 and they can be
measuring the scattered field on the breast. concluded as having significant effects with the confidence
of 0.95. Thus, Skin ε, Fat ε, BreastRadius and TumorRadius
are obtained as main concerns in the detection of breast
cancer.

Table 3 Analysis of the variance for the main effects

Sum of Mean p-value
Source of Variation d.o.f F Value
Squares Square Prob > F
Model 3349.53 55.00 60.90 12.56 < 0.0001
A-Skin ε 39.77 1.00 39.77 8.20 0.0055
B-Skin σ 17.34 1.00 17.34 3.58 0.0626
C-Fat ε 68.71 1.00 68.71 14.17 0.0003
Figure 1 CST design setup D-Fat σ 0.28 1.00 0.28 0.06 0.8093
E-Fibro ε 13.24 1.00 13.24 2.73 0.1029
The design points that are the combinations of 10 factors F-Fibro σ 0.08 1.00 0.08 0.02 0.8985
values ranging from their lower values to upper values given G-Tumor ε 10.19 1.00 10.19 2.10 0.1516
H-Tumor σ 7.22 1.00 7.22 1.49 0.2264
in Tab. 2 are generated by experimental design methods by J-BreastRadius 299.76 1.00 299.76 61.81 < 0.0001
using the Design Expert 7.0 Trial Version. Design space is K-TumorRadius 576.77 1.00 576.77 118.92 < 0.0001
used in the CST simulation model for assessing the return
loss values (S11). In order to find the input-output The graphs of the each significant factor’s main effect on
relationship, main effects and interactions of factor effects on the value of S11 is illustrated in Fig. 3. The factors
detecting breast tumor, S11 values obtained from the BreastRadius (J) and TumorRadius (K) seem to be more
simulation are entered as experimental design output values. influential than others on the change of the S11 value in terms
The flow of the method application in this study is given in of their slopes of the lines. However, the difference is that
Fig. 2. while the S11 value decreases through low-to-high values of
BreastRadius (J), the low-to-high values of the TumorRadius
Table 2 Lower and upper bounds for factor values
(K) increase.
Factor Name Low Level High Level
A Skin ε 30 40 In order not to illustrate all of the two factor interactions,
B Skin σ 3 9 only significant interaction effects of AJ, BD, CE, CJ, CK,
C Fat ε 1 10 EJ, EK, and JK are given in Tab. 4. The interactions of factors
D Fat σ 0 1 are important to be considered to demonstrate the effect of
E Fibro ε 40 50 two factors together on the value of S11. Hence, the
F Fibro σ 1.70 12
G Tumor ε 40 56 significance of two factors may result as lesser or greater than
H Tumor σ 3 15 each factor alone.
J Breast Radius (cm) 2.5 10
K Tumor Radius (mm) 1 10 Table 4 Analysis of the variance for significant interaction effects
Source of Sum of Mean p-value
d.o.f F Value
Variation Squares Square Prob > F
Model 3349.53 55.00 60.90 12.56 < 0.0001
AJ 44.98 1.00 44.98 9.27 0.0032
BD 19.92 1.00 19.92 4.11 0.0464
Interactions

CE 24.20 1.00 24.20 4.99 0.0286

CJ 75.75 1.00 75.75 15.62 0.0002
CK 64.90 1.00 64.90 13.38 0.0005
EJ 40.47 1.00 40.47 8.34 0.0051
EK 48.40 1.00 48.40 9.98 0.0023
JK 1838.38 1.00 1838.38 379.05 < 0.0001

Figure 2 Block flow diagram

In Fig. 4, the graphs of interactions from Tab. 4 are
3 RESULTS demonstrated. In the AJ interaction graph, Skin ε has no
significant effect on the S11 value for the small size
2k factorial design is used with V Resolution in this study. BreastRadius. However, for the large size BreastRadius, the
It means that each factor has two levels. In this experiment, S11 value increases through the low-to-high values of Skin ε.
there are ten factors, and in order to lessen the number of In the BD interaction graph, the S11 value increases at the
experiments, we can exclude some design points by using the high value of Fat σ through the low-to-high values of Skin σ
resolution property of the factorial design technique. Hence, . In the interaction graphs of CE, CJ and CK, the S11 value
the fractional factorial is used and 210−3 = 128 experiments increases through the low-to-high values of Fat ε for the high
are conducted. The analysis of variance (ANOVA) results in value Fibro ε, for the large size of BreastRadius and the small
Tab. 3 show that our model with a p-value less than 0.0001 size of TumorRadius, respectively. Similarly, in the graph of
represents the design space significantly. The p-values of the EJ and EK interactions, S11 decreases for the large size of

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 Nuşin UNCU, Emine AVŞAR AYDIN: THE EFFECTS OF DIELECTRIC VALUES, BREAST AND TUMOR SIZE ON THE DETECTION OF BREAST TUMOR

BreastRadius and the small size of TumorRadius through the less than for the small size. However, this interpretation
low-to-high values of Fibro ε. becomes reverse after the 8.5 cm size BreastRadius.
Finally, in the last graph, while BreastRadius is smaller However, the values of S11 for the large size TumorRadius
than 8.5 cm, S11 values for the large size TumorRadius are are greater than the small size.

Figure 3 Significant factors’ main effects on the detection of breast cancer

Figure 5 Desirability and optimum surface contours of S11

By using the numerical optimization tool of the Design The desired value of S11 is -21.8547. It is seen that the S11
Expert, the minimum value of S11 is found. In order to have value decreases at the given values of factors in Fig. 5, and
a minimum S11 value, the optimal design points are given in the increasing values of breast radius size and decreasing
Fig. 5. values of tumor size considerably help the detection of breast
The desirability graph based on two most effective tumor.
factors on breast tumor detection is demonstrated in Fig. 5.

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 Nuşin UNCU, Emine AVŞAR AYDIN: THE EFFECTS OF DIELECTRIC VALUES, BREAST AND TUMOR SIZE ON THE DETECTION OF BREAST TUMOR

Figure 4 Factors’ interaction effects

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4 CONCLUSION Conference of the IEEE Engineering in Medicine and Biology

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among females. Various research groups have focused on design approach of CST studio analysis for breast minimum
full electric field coverage. 2017 12th International Conference
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technique relies on the differences in the dielectric properties [7] Yousefnia, M., Ebrahimzadeh, A., Dehmollaian, M., &
of benign and malignant breast tissues which are skin, fat, Madannejad, A. (2018). A Time-Reversal Imaging System for
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carried out by using dielectric properties of skin, fat, fibro Transactions on Biomedical Engineering, 65(11), 2542-2551.
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different dielectric properties and different breast and tumor [9] Delbary, F., Brignone, M., Bozza, G., Aramini, R., & Piana, M.
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was considered in previous studies. The main factors such as Detection. Sensors, 18(2), 655. https://doi.org/10.3390/s18020655
fat and skin permittivity, breast and tumor size seem to be [11] von Hippel, A. R. (1954). Dielectric and Waves. MIT Press.
New York, 284p.
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[12] Nikolova, N. (2011). Microwave Imaging for Breast Cancer.
effects are crucial for observation. However, the effects of IEEE Microwave Magazine, 12(7), 78-94.
some factors change based on low or high the values of others https://doi.org/10.1109/MMM.2011.942702
are. For instance, although the effects of the factors fibro [13] Sha, L., Ward, E., & Stroy, B. (n.d.). A review of dielectric
permittivity, skin and fat conductivity are not significant properties of normal and malignant breast tissue. Proceedings
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through the low-to-high values of fibro permittivity with a https://doi.org/10.1109/.2002.995639
large size breast and a small size tumor, the return loss value [14] Surowiec, A., Stuchly, S., Barr, J., & Swarup, A. (1988).
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tissues. IEEE Transactions on Biomedical Engineering, 35(4),
skin and fat conductivity together increases the return loss
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value. [15] Campbell, A. M. & Land, D. V. (1992). Dielectric properties
In future experiments, the design points can be of female human breast tissue measured in vitro at 3.2
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lessen the number of factors and increase the precision of the https://doi.org/10.1088/0031-9155/37/1/014
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out by using the results of this study. Revıew of Experımental Desıgn in Analytıcal Chemıstry. Indo
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[18] Apfel, C. C., Korttila, K., Abdalla, M., Kerger, H., Turan, A.,
[1] Kwon, S. & Lee, S. (2018). Corrigendum to "Recent Advances
M. D., Vedder, I., Zernak, C., Danner, K., Jokela, R., Pocock,
in Microwave Imaging for Breast Cancer Detection".
S.J., Trenkler, S., Kredel, M., Biedler, A., Sessler, D. I., &
International Journal of Biomedical Imaging, 2018, 1-1.
Roewe, N. (2004). A Factorial Trial of Six Interventions for the
https://doi.org/10.1155/2018/1657073
Prevention of Postoperative Nausea and Vomiting. The New
[2] Kim, T., Oh, J., Kim, B., Lee, J., Jeon, S., & Pack, J. (2008). A
England Journal of Medicine, 350(24), 2441-2451.
study of dielectric properties of fatty, malignant and fibro-
glandular tissues in female human breast. 2008 Asia-Pacific https://doi.org/10.1056/NEJMoa032196
[19] Aslan, I. (2015). Design of Experiment (DOE) Case Studies in
Symposium on Electromagnetic Compatibility and 19th
Healthcare. International Review of Social Sciences, 3(7), 287-
International Zurich Symposium on Electromagnetic
303.
Compatibility. https://doi.org/10.1109/APEMC.2008.4559850
[3] Song, H., Men, A., & Jiang, Z. (2017). Breast tumor detection
using empirical mode decomposition features. IEEE Access, 1-
1. https://doi.org/10.1109/ACCESS.2017.2737633
[4] Kurrant, D. J. & Fear, E. C. (2011). Regional Estimation of the
Dielectric Properties of the Breast: Skin, Adipose, and
Fibroglandular Tissues. Proceedings of the 5th European
Conference on Antennas and Propagation (EUCAP), 2164-
3342.
[5] Chen, Y., Kosmas, P., & Martel, S. (2013). Microwave breast
tumor detection and size estimation using contrast-agent-
loaded magnetotactic bacteria. 2013 35th Annual International

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 Nuşin UNCU, Emine AVŞAR AYDIN: THE EFFECTS OF DIELECTRIC VALUES, BREAST AND TUMOR SIZE ON THE DETECTION OF BREAST TUMOR

Author contact:

Nuşin UNCU, Assistant Prof.

Adana Alparslan Türkeş Science and Technology University,
Department of Industrial Engineering,
Balcalı Mahallesi, Çatalan Caddesi No: 201/1,
01250 Sarıçam-Adana/Turkey
nuncu@atu.edu.tr

Emine AVŞAR AYDIN, Assistant Prof.

Corresponding author
Adana Science and Technology University,
Department of Aeronautics Engineering,
Balcalı Mahallesi, Çatalan Caddesi No: 201/1,
01250 Sarıçam-Adana/Turkey
+90-05318436781
eaydin@atu.edu.tr
rasvaenime@gmail.com

TEHNIČKI GLASNIK 13, 3(2019), 197-203 203

ISSN 1846-6168 (Print), ISSN 1848-5588 (Online) Original scientific paper
https://doi.org/10.31803/tg-20180908135420

DESIGN AND CONSTRUCTION OF THE PRESSURE SWIRL NOZZLE AND EXPERIMENTAL

INVESTIGATION OF SPRAY CHARACTERISTICS

Seyed Hadi SEYEDIN, Majid AHMADI, Seyed Vahid SEYEDIN

Abstract: This paper focuses on the structure and performance of the pressure swirl nozzle and the study of liquid atomization. In this study, the atomizer has been designed and
some experiments have been performed on it. Since image processing is an efficient method for measuring the size of the droplet and since it considerably reduces the total
measuring time and eliminates the subjective observer’s error in sizing and counting spray drops, a digital camera has been used for capturing images and image processing has
been done by the MATLAB software. The results show that by increasing the atomization air pressure, the spray angle increases and the droplet’s size decreases. It is concluded
that the spray angle is a function of the atomization air pressure and orifice diameter. Moreover, when the distance from the spray centre line increases, the droplet’s average
velocity decreases.

Keywords: atomization; droplet size; image processing; pressure swirl nozzle; spray

1 INTRODUCTION developed to model liquid sheet atomization with high Weber

and Reynolds numbers. The model considers a single phase
The prediction of droplet size distributions for of the liquid–gas mixture to represent the turbulent mixing of
atomization nozzles is important for the process design and the liquid sheet with the ambient gas [5]. Various measuring
the improvement of industrial spraying processes [1]. In one techniques such as laser doppler anemometry (LDA), phase
of the recent researches, the spray flow structure, droplet doppler particle analysis (PDPA) and computational fluid
Sauter mean diameter, and droplet impingement energy were dynamic (CFD) have been applied for modelling the
characterized at predefined axial distances and pressure turbulent mixing of the liquid sheet with the ambient gas. The
drops. It was found that the spray cone produced by the size of most spray drops is in the range of (10-1000) microns.
pressure swirl nozzles changes from a hollow cone to a full The technique of real-time image sensing and processing is
cone as the axial distance increases. The droplet’s size the one of the most promising methods to size and count such
initially decreases with the increasing of the axial distance small drops. By using this technique, one can store real-time
but subsequently increases in the investigated range of the images of the spray drops in a computer through a video
axial distance, while the droplet impinging Weber number camera. Subsequently, the stored information can be
decreases monotonously [2]. An experimental study on the analysed automatically. The main advantage of the technique
spray characteristics, including mass flow rate, spray flux is that the measurement and analysis can be performed in a
distribution, spray cone angle and drop size spectrum, was very short time. Furthermore, the subjective human error,
conducted. Based on the experimental data, the curves of the which is almost unavoidable in manual sizing and counting,
flow rate and spray cone angle versus the nozzle pressure can be eliminated so that it is possible to analyse sprays in
drop were obtained. Several typical spray flux distributions various environments by appropriate image processing.
were derived and the results indicated that the flux Despite these advantages, there are some basic problems
distribution changes significantly even with small pressure related to the system, resolution and light diffraction. On the
changes. Thus, it was proposed that the instability of the other hand, this is a rapid and available method in
spray flux distribution should be considered in the pressurizer comparison to the LDA and PDPA techniques [6]. In a new
[3]. In a new study, the spray cone-angle of the full cone paper on a better understanding of the injector performance,
nozzles is measured by the evaluation of images recorded the characteristics of the pressure-swirl atomizer were
with a camera by using the IMAGE J software. Correlations experimentally investigated and data were correlated to the
for the coefficient of discharge, spray cone angle and Sauter Reynolds numbers (Re) [7].
mean diameter are suggested on the basis of the experimental Image processing is not a quantitative method but it
results. [4] made an important contribution by making the full can give us a good idea about the spray pattern and droplet
linear stability analysis of a helical column of fluid in zero size. Nowadays, a high-speed photographic system can be
gravity and they successfully compared their prediction with built up by using almost only the conventional devices. A
the experimental data collected through high-speed imaging. simple set was successfully used to carry out tests on a group
The droplet size distribution is one of the most of pressure swirl nozzles. The camera does not need to have
important parameters of spray nozzles. The hollow conical high speed shutter capabilities. As a matter of fact, even
spray is made up of large droplets. According to the special high-speed shutters enable to "stop" the spray image
experiments, the recirculation zone contains the smallest because of the droplet’s velocity stream. The shutter is kept
droplets. In recent researches, the Eulerian model has been open while the trigger is pressed. The photo is taken in the

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darkness or by a black sheet at the back of spray. Moreover, where it gains a swirl motion, under which it leaves the exit
an investigation of spray characteristics such as the liquid orifice as a conical liquid sheet which consequently breaks
breakup length and spray cone angle of a charge-injected up into small droplets due to aerodynamic forces. The
electrostatic pressure-swirl nozzle has been conducted. The centrifugal motion of the swirling liquid makes a low-
liquid breakup length decreased, while the spray angle pressure area in the swirl chamber centre and generates an air
increased with an increase in the applied voltage and core along the centreline. The flow pattern inside the
injection pressure. An empirical equation to predict the atomizer is rather complex; it is a two-phase flow with
breakup length for the electrostatic pressure-swirl nozzle has secondary flow effects. There is a strong link between the
been suggested. The experimental result was within the range resulting spray characteristics and internal flow conditions;
of the predicted equation [6, 8].The above-mentioned two however, not all aspects of the internal flow are well realized
techniques are deducing the particle size information from [16]. Moreover, the pressure swirl and air-blast atomizers are
the optical signals scattered from an individual particle or a the two types of atomizers used in gas-turbine engines [17].
group of particles. In measuring volume, it is assumed that In recent years, some researchers studied the characteristics
all particles are spheres. Thus, basically, only the spherical of atomization for pressure-swirl atomizers of two various
particles should be processed with other techniques for geometries. The important effect of atomizer construction on
accurate measurement. On the other hand, in principle, the atomization process has been observed. Furthermore, a
various non-spherical particles can be processed through the guided experimental study reported that they aimed to
image processing technique because it is based on direct intensify the process of atomization and improve the
visualization and wide application is possible. Moreover, the properties of the spray [18].
measurement accuracy of the image processing techniques is
relatively insensitive to the optical properties of the particles 2 ATOMIZER DESIGN AND CONSTRUCTION
in comparison with the other techniques and optical
alignment is much easier [9]. In some cases, the simulation The two phases of atomizing including the following
program can be used in combination with calculation models stages and different sections of the atomizer have been shown
to predict the drop size depending on the hollow cone in Fig. 1.
nozzle's geometry and the volume flow for the atomization (1) Primary mixing of liquid and gas in the distributer
of Newtonian fluids [10]. In a new paper, the viscous flow (2) Secondary mixing in the mixing chamber
through the swirl chamber of a pressure-swirl atomizer has (3) Severe mixing in the spiral tube
been studied theoretically [11]. Additionally, the thermal (4) Liquid film formation in the cone cap
effects on the spray cone formation of a pressure swirl nozzle (5) Final atomization in the output of the nozzle tip.
in spray cooling have been investigated experimentally by
particle image velocimetry (PIV) [12]. Section (1) consists of two concentric tubes. Along the
The main purpose of the image processing is to develop internal tube, there are some holes to mix the liquid feed and
a simple appropriate algorithm to size and count the number atomizer gas. The liquid feed (water or vacuum gasoil) and
of spherical spray drops in the image frames, and emphasis the atomizer gas (air or steam) enter into the internal tube and
was placed on eliminating undesirable objects from the annular space, respectively, and mix together through the
image. Such objects included odd-shaped foreign materials holes existing on the internal tube. Then, the two-phase
and drops in contact or overlapping and parts of single drops mixture enters the section (3) which consists of a cylindrical
cut off by the image frame boundaries [6]. Therefore, this spiral surrounded by a connecting tube. This spiral produces
paper investigates the pressure swirl nozzle property and the a homogeneous mixture by circulatory movement and hard
application of a new image processing method for mixing at the opening of the orifice. Thus, the homogeneous
determining the droplet size distribution and droplet velocity mixture is atomized to a hollow conical spray after passing
distribution. The pressure of the liquid and gas mixture is the circular orifice. The orifice size and design have a main
measured in a mixing chamber by a pressure gauge. role in the droplet size and droplet velocity at the nozzle
outlet. The parameters for the design of the pressure swirl
1.1 Usage and Performance of Pressure Swirl Nozzle atomizer and operational variables are summarized in Tab. 1.

Pressure-swirl nozzles are used in a broad range of Table 1 Summary of the design parameters for the pressure swirl nozzle.
industrial uses, e.g. washing, cooling system, combustion Design data Spray Angle 60°
Length of the distribution tube 0.14 m
chamber, heavy fuel injection, painting and food processing, Number of holes in the distribution tube 15
etc. Their spray characteristics are approximately linked to Holes diameter 0.00075 m
the internal flow which predetermines the values of the liquid Length of the connecting tube 0.8 m
sheet formed at the outlet and discharge orifice. Pressure- Length of spiral 0.8 m
swirl atomizers are easy to make and prepare good Orifice shape conical
Cone angle 60o
atomization. They are frequently used in different Orifice hole diameter 0.001 m
applications where a large surface area of droplets is needed Orifice hole depth 0.005 m
or a surface must be coated by a liquid, e.g. combustion, fire Pressure of mixture 2 bar
suspension or air conditioning. In principle, the pumped Maximum liquid flow rate 6.5 L/h
liquid is injected via tangential ports into a swirl chamber Maximum gas flow rate 205 L/h

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The schematic drawing of the pressure swirl nozzle and After the investigation and modification of images, they are
its design characteristics are shown in Fig. 1. Here the processed by a R2014a version of the MAT LAB software.
pressure swirl atomizer is designed for gas oil having the
maximum flow rate of 6.5 L/s, the average injection pressure
of 2.5 bar and a half spray cone angle of 30°, and the material
is made from stainless steel for the prevention of corrosion.

Figure 2 The schematic representation of the pressure swirl nozzle and the
performance analysis system

4 PHOTOGRAPHY AND IMAGE PROCESSING METHOD

In this study, a digital camera is used. Furthermore, for

the sharper spray image, a black plastic retain is used at the
back of the nozzle. This part is useful for visualizing the
transparent spray droplets.
Before image processing, the following steps for image
preparing must be conducted:
1) Shooting (taking a photograph) from the nozzle spray
2) Preparing and modifying the image for better resolution
Figure 1 The schematic drawing of the pressure swirl nozzle (1) Distributer tube 3) Checking images and obtaining the necessary
(2) Mixing chamber (3) Spiral part (4) Nozzle conical cap (5) Nozzle orifice information.

3 THE EXPERIMENTAL SET-UP The schematic image of spray droplets after photography
is shown in Fig. 3
The experimental set-up is shown in Fig. 2 .The air with
high pressure exits from the compressor, passes through the
tube and enters into the liquid pressure vessel. In Fig. 2, the
schematic images of various equipment used in the pressure
swirl nozzle’s performance analysis are shown.
When the sprayed stream exits the nozzle orifice, the
images of produced droplets are captured by a digital camera.

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the equation is multiplied by 1200. To our knowledge,

velocity is displacement divided by time (meter per second,
here Δt = 1/1200 and Δx = x2 – x1). Moreover, the mean
velocity of droplets is calculated by the average velocity of
droplets, in each area of the frame. Droplet displacement in
two consecutive frames for measuring velocity is shown in
Fig. 4.

4.2 Calculation of the Mean Droplet Size (MDS)

The high quality digital images were captured from the

spray for MDS calculation. The original images were
converted to black and white (BW) images. Each white
Figure 3 The model image of spray droplets containing undesirable objects
colour has a pixel value equal to 1 and each black colour has
the pixel value equal to 0 (i.e., an image includes the 0 and 1
4.1 Calculation of the Mean Droplet Velocity (MDV) matrix). The droplet shape is assumed to be elliptic.
Therefore, by having the area of (A) and ellipse eccentricity
For calculating MDV, the first shooting from the spray of (e) for a droplet in a black and white image, the diameter
by means of a high speed camera (Casio Exilim-1200 frame of the droplet is calculated by using the MATLAB software
per second) was done. Film or video frames were then and image processing toolbox. The droplet is more spherical
extracted by a computer. After this step, the movement of in shape as the parameter of (e) approaches to 1.
droplets from one frame to the next one was computed based
2
on the pixel unit and it was converted to the metric unit. b
Droplet displacement value was then divided by time A π ab  ,    =
= e 1−   (2)
a
(seconds) to calculate the velocity droplet by using the Eq.
(1):
In Eq. (2), a and b are half of the large and small
diameters of the oval object. The droplet shape is shown in
x2 − x1
=V  × 1200 m/s (1) Fig. 5, and it is near the elliptic shape.
pix × 100

Figure 5 Droplet surface is approximately equivalent to the oval area

In Fig. 6, two models of connectivity for calculating the

droplet size by means of the image processing method has
been presented. The droplets are white and the image
background has the black colour (BW image). The 0 and 1
matrix for image processing is presented in Fig. 6 (SE is the
structure element in MATLAB).

Figure 4 Calculation of droplet displacement in two different consecutive frames: a)

Previous frame. b) Next frame, captured by Casio Exilim Pro EX-F1 high
speed digital camera, 6.0 MP, 1200 fps

In Eq. (1), x is the droplet distance that transfers based

on the pixel in the digital image. The pix is the number of
pixels that is equivalent to 1 cm and this formula is divided
by 100 for converting to the meter unit (SI). They are
Figure 6 (a) The 0 and 1 matrix of the BW image. (b) Two types of pixels’
calculated by the MATLAB image processing toolbox based connectivity in the MATLAB Software for image processing, 4th and 8th connectivity
on the pixel unit. It takes the time of 1/1200 second for the [14]
droplet to move from one frame to another frame; therefore,

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The initial image includes RGB image and grey levels Thus, the length and width of the centre of each drop are
(between 0 and 1) must be converted to the BW image. Each derived from Eq. (3).
image must be bmp (2D format) before processing.
Therefore, there is a matrix from the image including 0 and n n
1. Non-isolated droplets (i.e. droplets in overlap condition, or=
=
X =
∑ xi
i 1=
,  Y
∑ y
i 1 i
(3)
droplets in contact) are all eliminated and the holes (empty n n
spaces) of drops are filled by the same pixels.
For segregation or better separation of pixels and proper Where xi and yi are the length and width of the droplet
image investigation, the Sobel function in MATLAB is used. pixels, respectively. n is number of pixels that include the
In Fig. 7, the Sobel modification method for accurate analysis droplet.
is shown. After this step, the image processing operation
starts and the information is derived. 4.3 Determination of the Spray Angle

The number of pixels in the longitudinal and cross

directions of spray cone should be measured. The spray angle
was calculated by the MATLAB image processing toolbox
(Fig. 9).
In Fig. 9, θ is the angle between the spray centre line and
the external edge of the spray cone which represents the half
spray cone angle, and it is calculated by the Eq. (4).

a
θ = 2 arctan   (4)
Figure 7 Image for displaying the Sobel method performance b  

The Sobel method is a linear algorithm of edge detecting, The spray angle, θ, depends on the air pressure and air
which determines the boundaries of the light and dark points flow rate. In dilute solutions, the air flow rate influence is
of an image. The Sobel command is used in MATLAB as a more dominant than that of the liquid. Because the shear
function for image processing. The change in pixel gradients forces from the air flow are exerted on the liquid sheet in the
of an image is applied by the Sobel method for a complete nozzle head, where the mixture of air and liquid is spread out
separation of BW pixels before processing. In Fig. 8, from the nozzle orifice, it atomizes into small droplets.
different stages for preparing image (before processing) are
shown. The main image changed into BW and the Sobel
method is applied to separate the boundary between the dark
and light spots in an image for better processing and more
accurate results.

Figure 9 Determination of the spray angle by the MATLAB Image Processing

toolbox. Longitudinal and cross distances from the spray centre are shown in the
pixel unit.

The programming algorithm for image processing is

shown in Fig. 10.

Figure 8 Better separation of a droplet in a BW image by the Sobel method

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D10 D=
=
∑ 0Di (5)
mean
Ni

In which i is the measured point in the spray’s cross-

section, Di is the sample diameter in each point of surface and
Ni is the total number of sampled droplets in the spray area.
The measurements gave a minimum droplet size at the spray
axis and an increase of size towards the edges of the spray.
Fig. 12 presents the experimental measurements by the image
processing method in different distances. The droplets near
to the central axis of the spray for the axial distance from the
nozzle tip were very small. A possible reason could be the
difficulty of measuring the smaller droplets with the image
processing method. Moreover, in this method, the over-
estimation of the mean diameter in the edge of the spray is
observed. Fig. 12 shows that the calculated mean diameter
increases regularly when increasing the distance from the tip
of the spray nozzle and the experimental spacemen.
Measurements also show a rising trend at the distance of 8
cm.

5.1 Results of the Mean Droplet Diameter

The droplet’s mean diameter was calculated by the

image processing method and the results are compared and
presented in Fig. 13 and Tab. 2. It is concluded that the
applied camera apparatus can measure the values of the mean
Figure 10 Flowchart for pattern recognition
diameter at threshold locations with difficulty (centre and
edge) of the spray at this distance (8 cm). At the distances of
5 RESULTS AND DISCUSSION
14 cm and 20 cm from the nozzle tip, the dispersion of the
droplet’s diameter is increased by increasing the radial
The droplet size and velocity distribution was obtained
position due to the vortex flow of the surrounding air (Fig.
in different distances from the nozzle tip (8, 14 and 20 cm,
12).
respectively) through the cylindrical space beneath the
nozzle orifice. The experimental values related to image
processing will be discussed. Fig. 11 represents the radial
evolution of the mean diameter at different distances from the
tip of the nozzle.

Figure 12 Droplet mean diameter in the radial coordinate, in different distances

from the nozzle tip.
Figure 11 The sketch of the droplet position in each cross section of the spray.
The experimental results for the mean diameter of the
The mean diameter of droplets at each point in the spray droplets are shown in Tab. 2. Moreover, Fig. 12 shows that
cross-section is calculated by the Eq. (5). as the spray cone section is set farther from the nozzle orifice,

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the droplet mean diameter has some fluctuations in the results show that as the spray cone section is set farther from
droplet size. the nozzle orifice, the droplet mean velocity decreases. The
liquid flow in the orifice centre is fast and near the orifice
Table 2 The mean diameter of the droplets in different distances from the nozzle tip walls, and it decreases due to the wall effects. As a result of
Distance (cm) Mean Diameter (μm) the mean droplet velocity, this velocity decreases. In the
8 25.02
14 24.5
spray cone centre line, the velocity reaches the maximum.
20 26.09 Since the spray jet is in the straight trajectory and away from
the spray cone centre, the spray stream angle causes the
5.2 The Results of the Mean Droplet’s Velocity droplets’ movement in more distances than the one of a
straight line and the mean droplet velocity decreases.
Due to the existence of air-cored vortex in the pressure
Table 3 The mean velocity of the droplets in different distances from the nozzle tip
swirl atomizer, the droplet number concentration is high at
Distance (cm) Mean Velocity (m/s)
the region near the axis of the spray. Fig. 13 shows the radial 8 14.9
distribution of the droplet mean velocity. At the centre of the 14 6.9
spray cone, the droplet velocity is high and reduces towards 20 5.05
the edge of the spray. A relatively uniform velocity
distribution of droplets in the spray is observed. At the axial 5.3 Calculation Number Density as Radial Distribution
distance of 8 cm, the calculated mean velocity of the droplets
at the centre is larger than the measured results at the edge of Fig. 14 shows the predicted number density of the
the spray. This is due to the over-estimation of the mean droplets at each cross-section. The number density
diameter which is depicted in Fig. 13. At the axial distance distributions are defined by dividing the number of the
of 20 cm, the calculated mean velocity of the droplets at the droplets in each interval by the total number of droplets
centre of the spray is smaller than the measured results. This accommodated on the circle radius of the cone section. The
might be because of the uncertainty associated with the number density is the percentage of the droplets’ number to
model implemented within the experimental results which the whole number, in different intervals. It is considerable
may have out layer points. The mean velocity of droplets at that the number of drops is more at the area near the spray
each interval in the spray cross-section is calculated by the centre, rather than other points, and is an indicator of the swirl
Eq. (6). motion of air-liquid mixture, which is counted as a feature of
the nozzle. Moreover, at intervals of 14 and 20 cm, the
N distance of droplets increases from the spray cone centre and
VAvg =
∑ i =1vi (6) the number of drops reduces at that area, which is why the
N number density reduces as well.

The vi is the droplet velocity, N is the number of droplets

and VAvg is the mean velocity in each area of the spray.

Figure 14 Radial distribution of the number density at different zones of the

nozzle's output - image processing

In the distances of 14 and 20 cm, the number of drops on

that surface is reduced and consequently the number density
Figure 13 Droplet mean velocity distribution in the redial coordinate in various is reduced, i.e. the pressure swirl nozzle has a hollow cone
distances from the nozzle tip spray pattern.
The experimental results are based on the mean velocity
at each section and are shown in Tab. 3 and Fig. 13. The

210 TECHNICAL JOURNAL 13, 3(2019), 204-212

 Seyed Hadi SEYEDIN et al.: DESIGN AND CONSTRUCTION OF THE PRESSURE SWIRL NOZZLE AND EXPERIMENTAL INVESTIGATION OF SPRAY …

5.4 Air Pressure Changes and their Effect on the Pressure increasing the distance from the nozzle's head. The average
Swirl Nozzle velocity of drops is reduced gradually by increasing the air
pressure. By means of decreasing the droplet velocity, the
Fig. 15 shows the changes in the spray angle versus the number of collision is reduced and the average number of
air pressure for the pressure swirl nozzle system. The average drops from the centre to the edges of the spray cone increases
value of the spray angle for this nozzle is about 41 degrees, gently. Furthermore, near the edge of the spray cone, the
for Lacava et al., it is 27 degrees and for Digvijay et al., it is drops’ size varies as a result of the existing produced vortex
32 degrees. The percentages of the relative difference of the in the surrounding air of the jet spray, resulting in the drop
spray angle in this research in comparison with these two size distribution. The advantage of the image processing
works (Lacava and Digvijay) are 33% and 21%, respectively method is that it is cheap and available. The accuracy and
[15, 16]. quality of the images is related to the environmental
The reason behind this difference is the different conditions such as light and digital camera. The results
structure of nozzles, equipment type and experiment showed that by increasing the atomization air pressure, the
operational conditions. spray angle increases and it is predicted that the droplet size
decreases because of an increase in droplet velocity and more
collision of the droplets with each other and the orifice wall
at the outlet of the nozzle. It is found that the spray angle is a
function of air pressure and the orifice diameter of the
nozzle's head. Moreover, by increasing the distance from the
spray centre, the droplets’ average velocity decreases
because the outlet droplets’ contact the edges of the nozzle
orifice and air friction factor decrease their velocity.

Acknowledgement

The authors would like to thank Masoud Kambarani and

Seyed Hasan Alhoseini for their assistance and guidance with
the experimental set up and their contributions to the
research.
Figure 15 Effect of injection pressure on the spray cone angle
Nomenclatures
In this section, a simple experimental correlation is
provided for determining the angle of the nozzle spray V Velocity (m/s)
according to the curve in Fig. 15. Eq. (7) is used for Pix Number of pixels equivalent to 1 cm
determining the spray angle in pressure-swirl nozzles. X Distance by the pixel unit (Pixels)
A Area (m2)
  p 0.7058   d 0−0.452
θ = 1.1439 (7) a Half of a large diameter in oval
b Half of a small diameter in oval
In this equation, pressure is in the bar and orifice n Number of pixels
diameter of the nozzle's head and it is measured in meters. x Length of drops based on the pixel
The Reynolds number value was bigger than 2300, and the y Width of drops based on the pixel
flow was fully turbulent. This equation follows the power θ Spray angle (Degree)
law and it has been computed as the data fitting program by p Air pressure (bar)
the MATLAB software and it is better to use it for low d0 Orifice diameter (mm)
viscosity liquids and turbulent flows. The novelty of this D10 Mean diameter (µm)
work is the use of the precision digital camera and the image N Number of droplets
processing method for calculating the spray characteristic,
which is an available, fast and inexpensive way and also an 7 REFERENCES
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ISSN 1846-6168 (Print), ISSN 1848-5588 (Online) Original scientific paper
https://doi.org/10.31803/tg-20190513114458

CUTTING PERFORMANCE OF DEEP CRYOGENIC TREATED AND NITRIDED HSS CUTTING

TOOL INSERTS

Sanja ŠOLIĆ, Zdravko SCHAUPERL, Vlado TROPŠA

Abstract: High speed steel (HSS) is a very important industrial tool material and has been constantly improved for different wear resistance applications and cutting tools, i.e.
drills, milling cutters, hobs and for the cutting tools in which the economical cutting speed is too low for choosing the carbide tools. The properties of HSS depend significantly on
the parameters of the conducted heat treatment. In this paper, the influence of deep cryogenic treatment in combination with nitriding of metallurgical powder metallurgy HSS on
the wear resistance was measured. Additionally, the cutting performance in a single point cutting tool machinability test at the configuration of the dry low-speed turning of steel
was investigated. The results showed that deep cryogenic treatment itself, and in combination with nitriding, resulted in the reduction of the wear rate. The results of the single
point cutting tool machinability test showed that deep cryogenic treated and nitrided HSS inserts performed worse than the classically heat-treated inserts and deep cryogenic
treated HSS inserts exhibited approximately the same flank wear as the nitrided ones.

Keywords: deep cryogenic treatment; cutting tools; high speed steel; nitriding; wear resistance

1 INTRODUCTION to annealing during machining. It is the result of the plastic

deformation of the surface which leads to subsurface crack
High speed steel (HSS) is a very important industrial tool nucleation, propagation and fallout of wear particles from the
material and has been constantly improved for different wear tool surface. Wear due to chemical instability occurs with
resistance applications and cutting tools, i.e. drills, milling high cutting speeds and high cutting temperatures [2].
cutters, hobs and for the cutting tools in which economical The properties of high-speed steels depend significantly
cutting speed is too low for choosing the carbide tools. When on the parameters of conducted heat treatment [4].
cutting, the tool moves through the material of the workpiece Authors in [5] reported that using different heat
by removing the chip from its surface. The tribological treatment parameters with different additional heat treatment
conditions that appear in the contact between these two and thermo-chemical processes increases tool steel
surfaces in mutual motion are very demanding. The contact properties and its wear resistance and can be adjusted for
temperature of steel machining can range from 900 °C to specific application. The application of deep cryogenic
1300 °C [1-3]. According to Holmberg et al. [1], 80% of the treatment (DCT) in the heat treatment of high speed steel
heat produced in the machining process is caused by the tools has resulted in increased wear resistance and
mechanical deformation of the chip, 18% by friction between dimensional stability of the treated material [6, 7].
the chip and the upper surface of the tool and only 2% is Combining DCT with various austenitization temperatures
created on the tool tip. Of the heat eliminated, about 75% is results in a different volume of retained austenite which
eliminated by the chip, 5% is absorbed by the workpiece and affects the hardness and fracture toughness [8, 9] of certain
20% is conducted through the tool, but note that these values tools, but it can also affect the enhancement in wear
change depending on the processing conditions, mostly speed resistance regardless of the hardness [10, 11].
and feed. Generally, there are four main mechanisms of tool In the recent years, numerous authors have studied the
wear that are present in metal cutting tools, namely abrasive influence of deep cryogenic treatment on a variety of HSS
wear, adhesive wear, delamination wear and wear due to and tool steel properties. Authors in [8] compared the wear
chemical instability, including diffusion, solution and behaviour of a vacuum heat treated and the deep cryogenic
electrochemical wear [2, 3]. treated at −196 °C ESR AISI M2 HSS in combination with
Abrasive wear takes place on tool surface and is caused four different tempering temperatures. The presented results
by hard particles, usually carbides, oxides and some silicates showed that in general, DCT samples had better wear
in the work material, and it is responsible for the tool flank resistance compared to the vacuum heat treated samples with
face wear. Abrasive wear appears in the same amount improvement in their fracture toughens and hardness.
regardless of the cutting speed and cutting temperature. The Authors in their review [12] concludes that the improvement
adhesive wear of cutting tools is the result of the formation gained by DCT is mainly due to the complete elimination of
of micro-welded joints between the chip and the tool face and the retained austenite and the formation of nanometre sized
the breaking of joints by the shearing force which tears out carbides dispersed in the tempered martensitic structure.
particles of tool material and adheres it to the chip or the Authors [13] investigated the influence of different heat
workpiece. Adhesive wear occurs in low cutting speeds at the treatment parameters (austenitizing temperature, cooling
flank face of the tool when contact temperatures are not very rate, holding time, heating rate, and tempering temperature)
high. Delamination wear occurs when HSS tools soften due which all directly influence the effect of DCT on tool steel

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 Sanja ŠOLIĆ et al.: CUTTING PERFORMANCE OF DEEP CRYOGENIC TREATED AND NITRIDED HSS CUTTING TOOL INSERTS

properties. The results showed that the most significant DCT, it could eliminate the advantageous influence of deep-
parameters in terms of mechanical properties are cryogenic treatment.
austenitizing and tempering temperatures. A low It is clear that an optimized combination of cryogenic
austenitizing temperature combined with a high tempering treatment temperature and time, cooling rate, and subsequent
temperature improves fracture toughness, bending strength tempering would make the best of sub-zero treatment while
and elongation, while the high austenitizing and low balancing the cost and performance of the material.
tempering temperatures improve hardness and wear The purpose of this paper is to study the influence of
behaviour. deep cryogenic treatment, in combination with nitriding, of
Authors in [14] analysed the influence of DCT with powder metallurgy high speed steel on the wear resistance
different austenitizing and tempering temperatures on and cutting performance in a single point cutting tool
fracture toughness, hardness and wear resistance of PM machinability test at the configuration of the dry low-speed
lower C, high W and Co cold work tool steel, high C and V turning of steel.
PM cold work tool steel and PM HSS. They reported that in
the case of low carbon cold-work tool steel, the DCT results 2 MATERIALS AND METHODS
greatly improved in fracture toughness, while maintaining
high hardness, which can be linked to the formation of finer The material used in this study was a high speed steel
needles such as martensite and martensitic transformation produced by powder metallurgy, grade PM S390 MC. The
accompanied by plastic deformation of the primary chemical composition of steel is presented in Tab. 1.
martensite. On the other hand, for high C cold-work tool
steel, the DCT has a negative effect, while for high-speed Table 1 Chemical composition of the PM S390 MC high speed steel
steel, the DCT has virtually no impact on its properties. They %C % Si % Mn % Cr % Mo % V % W % Co % Fe
1.64 0.60 0.30 4.80 2.00 4.80 10.40 8.00 rest
also reported an alteration in fracture toughness/Rockwell
hardness ratio which affects wear resistance of cold-work
For wear resistance-testing, disc shaped samples were
tool steel. It was concluded, however, that hardness is still a
prepared with the dimensions of ∅22×4 mm. For the purpose
major parameter affecting abrasive wear resistance.
of a single point cutting tool machinability test or turning test,
The application of DCT to HSS cutting tools has been
20 cutting tool inserts were prepared according to the ISO
enhanced in the recent years due to its effect in the prolonging
13399, CNMA 120408, Fig. 1, with the dimensions shown in
of tool life, dimension stability and stress relief. Authors in
Tab. 2.
[15] reported that the M2 HSS twist drills tool life increased
for approximately 280 % when drilling steel, taking the total
failure of tools as a criterion for determining the tool service
life. Authors in [16] reported a 77 % and 126 % improvement
tool life of DCT and tempered M2 tool steel drills.
Authors in [17] investigated the combined impact of the
cryogenic temperature with tempering on the mechanical
properties and wear resistance of the W9 HSS. They
Figure 1 Insert CNMA 120408 [18]
concluded that all varieties of DCT influenced the wear
resistance and hardness of W9 HSS. The performance of the Table 2 CNMA 120408 insert dimensions
W9 HSS taps during the tapping test was not notably Grade L, mm IC, mm S, mm RE, mm
influenced by the DCT temperature. It was shown that tool CNMA 120408 12.9 12.7 4.76 0.8
life was the longest when treated in the temperature range of
−196 to −160 °C with subsequent tempering, and it was The heat treatment was performed in an Ipsen vacuum
concluded that for treatment effectiveness and cost furnace with the preheating parameters 650 °C / 30 min, 850
efficiency, the deep cryogenic treatment at −160 °C could be °C / 20 min, 1050 °C / 15 min before the heating to the
the optimal choice. austenitization temperature. The heating rate to the
Authors [5] investigated the impact of different time and austenitization temperature of 1130 °C was 5 °C/min and the
temperature DCT parameters and the combination of DCT austenitization lasted 6 min, after what samples were
and plasma nitriding on the wear performance of powder– quenched in the nitrogen flow, p = 1050 mbar. The heat
metallurgy HSS considering the wear resistance and treatment parameters are presented in Tab. 3.
resistance to galling under dry sliding conditions. They
concluded that DCT improves the microstructure of PM HSS Table 3 Heat treatment parameters
Austenitization, Deep cryogenic Tempering, Nitriding,
generating the finer needle-like martensitic structure, which Batch
°C/min treatment, °C/h °C/h °C/h
results in higher hardness and better wear resistance 520 / 520 /
HT 1130 / 6 min -
properties, especially considering friction, and galling 490 / 2 h
resistance against stainless steel which considerably HTN 1130 / 6 min -
520 / 520 /
490 / 2.5 h
improves with longer cryogenic treatment times. They also 490 / 2 h
DCT 1130 / 6 min −196 °C / 24 h 520 / 2 h
concluded that plasma nitriding improves tribological DCTN 1130 / 6 min −196 °C / 24 h 520 / 2 h 490 / 2.5 h
properties of PM HSS and reduces the effect of austenitizing
temperature, but the results indicated that if combined with

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After quenching, part of the test samples were soaked in treatment resulted in a 23.6 % reduction of the wear rate.
liquid nitrogen at a controlled speed and left for 24 h, Nitriding resulted in an approximately 18.4 % reduction of
followed by single tempering. Other samples were tempered the wear rate and in combination with DCT 25.6 %
three times. Part of the vacuum and deep cryogenic treated respectively.
samples were plasma nitrided (95% H2 and 5% N2). Nitriding
in the duration of 2.5 hours was carried out at a temperature
of 490 °C in a Metalplas Ionon BDAG GRUPPE BALCKE-
DÜRR AG apparatus. After heat treatment, thorough
analysis of the microstructure and mechanical properties was
performed on samples and the results were published in [19].
Wear resistance of specimens was determined by
simulating two-body abrasive wear by alternating the sliding
motion by using ball-on-flat contact with the Al2O3 ball as a
counter-body with a hardness of 1200 HV and a diameter of
∅10 mm. Wear tests were performed under dry sliding
conditions at an average sliding speed of 0.024 m/s with a
frequency of 5 Hz and amplitude of 2.4 mm, maximum
contact pressure of 1300 MPa (FN = 10 N) and total sliding
distance of 30 m, Fig. 2. Test results were evaluated in terms Figure 3 Flank wear of the tool, VB
of the samples’ wear rate (mm3/Nm) and average coefficient
of friction. Testing was performed at room temperature (22 The results show that nitriding after deep cryogenic
°C) and relative humidity of 40 %. treatment did not significantly influence the reduction in
wear rate as it influenced the wear rate after heat treatment.
Regarding the coefficient of friction, DCT samples had a bit
higher coefficient of friction, approximately 4 % higher than
classically heat-treated samples. Through nitrogen diffusion
layer formation [19, 20], plasma nitriding reduced friction
coefficient of the analysed steel in classic heat-treated
samples (HTN) and DCTN samples for 8 % and 11 %,
respectively.
Figure 2 Schematic diagram of ball-on-flat wear test

The single point cutting tool machinability test was

performed at the CNC turning machine SBL 500 TRENS
with the parameters presented in Tab. 4. The material of the
workpiece used in this test was annealed X210Cr12 steel
with a hardness of 240 HB.

Table 4 Turning parameters

Cutting speed, Depth of cut, Feed,
Turning X210Cr12 steel with
m/s mm mm
HSS tools
30 0.5 0.1

For every heat treatment batch, five HSS tool inserts Figure 4 Wear rate and Friction coefficient
were used with two cutting edges. Tool wear was measured
after every two minutes of turning by measuring the flank Fig. 5 presents the values of the average flank wear of
wear, VB, by using the Tescan Vega TS5136LS scanning the cutting tool inserts measured every two minutes of
electron microscope. The criterion for the end of tool life was turning. The results show that after two minutes, heat treated
the catastrophic failure of five 2-minute cycles of turning, i.e. (HT) inserts had the highest value of average flank wear, but
a total of 10 minutes. VB was the width of the flank wear after four minutes of turning, the cryogenically treated and
track at the edge of the flank, Fig. 3. The results represent the nitrided (DCTN) tool inserts had higher flank wear values
mean value of ten measurements. than the heat treated (HT) ones. The heat-treated inserts (HT)
and cryogenically treated and nitrided (DCTN) inserts had
3 RESULTS AND DISCUSSION total tool failure after eight minutes of turning with flank
wear values above 1.2 mm. The DCT inserts and heat-treated
The results of the abrasion wear testing show that DCT and nitrided (HTN) inserts exhibited similar wear behaviour
and nitriding resulted in lower wear rates of the high-speed with slightly lower flank wear values for the heat-treated and
steel specimens tested against alumina ball counter-body. nitrided (HTN) tool inserts. When compared with the
The results are presented in Figure 4. Deep cryogenic

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 Sanja ŠOLIĆ et al.: CUTTING PERFORMANCE OF DEEP CRYOGENIC TREATED AND NITRIDED HSS CUTTING TOOL INSERTS

laboratory wear test results, it can be observed that the DCT pronounced at a higher rate and they contributed to the
samples had a lower wear rate than the HTN samples and that intensity of the cutting tool insert flank face wear.
the DCTN samples exhibited the lowest wear rate of all Fig. 6 shows wear of the cutting inserts flank face and
samples, and in the machinability test, the DCTN tool inserts the formation of a build-up edge of the flank face in all four
had the poorest wear behaviour. Similar results were reported cutting inserts can be observed. The build-up edge is formed
in [5], where it was concluded by the authors that plasma as a result of indirect adhesion wear [21].
nitriding enhances the tribological properties of powder Adhesion wear is one of the tool wear mechanisms that
metallurgy HSS, but if combined with the DCT, it might can be present in a wider range of cutting temperatures. It can
reduce the advantageous effect of the deep-cryogenic be produced by two different ways. Direct adhesion wear is
treatment and the reasons for that are not clear at present. caused by the integration of tool particles to the chips, and
indirect or secondary adhesion wear is caused by an
integration of a fragment of the workpiece material to the
tool. This affects tool wear in the way that tool geometry is
altered by material integration and when these fragments are
removed, they can extract tool particles causing tool wear
[21]. As observed in Fig. 6 d, the highest build-up edge after
four minutes of turning is present at the DCTN insert even
though DCTN samples had the lowest coefficient of friction
in the laboratory wear test. This is also in accordance with
[5], where it was concluded after the laboratory wear tests
performed on samples, that plasma nitriding in combination
with DCT might eliminate the advantageous effect of DCT,
leading to reduced galling resistance. Galling resistance
reduction also had a large influence on the results in the
Figure 5 Average flank wear of differently heat treated HSS cutting tool inserts machinability test performed within this research since
galling is a very intense form of adhesion wear. Adhesion
wear leads to the formation of a build-up edge of the tool
flank face intensifying the wear of the cutting tool.

4 CONCLUSION

Properly optimized and conducted heat treatment can

notably affect the properties of high-speed steels. The heat
treatment parameters of HSS are chosen depending on the
required specific properties of the particular tool. With
a) b) different combinations of deep cryogenic treatment
parameters and nitriding, it is possible to affect the
mechanical properties (hardness and fracture toughness) of
certain components, but it can also increase wear resistance
regardless of the changes in hardness values.
In this paper, the influence of nitriding in combination
with deep cryogenic treatment on the abrasion wear
resistance and coefficient of the friction of high-speed steel
produced with powder metallurgy was investigated. In
addition to that, its behaviour under the realistic wear
c) d) condition, i.e. the cutting process, was observed, by
Figure 6 Flank wear of differently HSS heat-treated inserts performing the single point cutting tool machinability test
a) Classically heat treated HSS; b) Classically heat treated and nitrided HSS and measuring the flank wear every two minutes. The results
c) Deep cryogenic treated HSS; d) Deep cryogenic treated and nitrided HSS
showed that deep cryogenic treatment resulted in a 23.6 %
reduction of the wear rate and nitriding in an approximately
Although the laboratory tests gave the results on wear
18.4 % reduction of the wear rate, in combination with the
behaviour of the cryogenically treated and nitrided HSS, they
deep cryogenic treatment of 25.6 % respectively. The results
cannot predict the behaviour of HSS tools under the realistic
show that nitriding after deep cryogenic treatment did not
wear condition, e.g. cutting processes which involve high
influence significantly the reduction in the wear rate as it
temperatures at the tool – chip contact, high stress on the tool
influenced the wear rate when conducted after the heat
surfaces and intense interaction between the tool and the
treatment. Regarding the coefficient of friction, deep
workpiece. It is clear that at the cutting speed of 30 m/min
cryogenic treatment samples had an approximately 4 %
diffusion and oxidation, wear mechanisms were also
higher coefficient of friction than the classically heat-treated
samples. Plasma nitriding reduced the friction coefficient of

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 Sanja ŠOLIĆ et al.: CUTTING PERFORMANCE OF DEEP CRYOGENIC TREATED AND NITRIDED HSS CUTTING TOOL INSERTS

the analysed steel in the classically heat-treated samples and the properties of tool steel. J. Mater. Process. Technol., 118,
deep cryogenic treated samples for 8 % and 11 %, 350-355. https://doi.org/10.1016/S0924-0136(01)00973-6
respectively. Regarding the behaviour of HSS in the [11] Mohan Lal, D., Renganarayanan, S., Kalanidhi, A. (2001).
Cryogenic treatment to augment wear resistance of tool and die
machinability test, the heat-treated (HT) inserts and deep
steels. Cryogenics, 41, 149-155.
cryogenic treated and nitrided (DCTN) inserts exhibited a https://doi.org/10.1016/S0011-2275(01)00065-0
total tool failure after eight minutes of turning with flank [12] Baldissera, P. & Delprete, C. (2008). Deep Cryogenic
wear values above 1.2 mm. Treatment: A Bibliographic Review. The Open Mechanical
DCT inserts and heat-treated and nitrided (HTN) inserts Engineering Journal, 2, 1-11.
exhibited similar wear behaviour through the machinability https://doi.org/10.2174/1874155X00802010001
test with slightly lower flank wear values for the heat-treated [13] Oppenkowski, A., Weber, S., & Theisen, W. (2010).
and nitrided (HTN) tool inserts. When compared to the Evaluation of factors influencing deep cryogenic treatment that
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[14] Podgornik, B., Paulin, I., Zajec, B., Jacobson, S., & Leskovšek,
the DCTN samples exhibited the lowest wear rate of all V. (2016). Deep cryogenic treatment of tool steels. Journal of
samples and in the machinability test, the DCTN tool inserts Materials Processing Technology, 229, 398-406.
had the poorest wear behaviour. https://doi.org/10.1016/j.jmatprotec.2015.09.045
Based on the results of the machinability test, it can be [15] Silva, F. J., Franco, S. D., Machado, A. R., Ezugwu, E. O.,
concluded that when high-speed steel is subjected to Souza, A. M. J. (2006). Performance of cryogenically treated
conditions in the real cutting process, classical heat treatment HSS tools. Wear, 261, 674-685.
and nitriding have the same effect as DCT and in https://doi.org/10.1016/j.wear.2006.01.017
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of deep cryogenic treatment on wear resistance and tool life of
advantageous effect of the deep-cryogenic treatment.
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tribological properties of cutting tools, doctoral thesis, Zagreb, [20] Kato, H. & Eyre, T. S. (1994). Sliding wear characteristics of
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Microstructural changes in heat treatment of PM high-speed [21] Gómez-Parra, A., Álvarez-Alcón, M., Salguero, J., Batista, M.,
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[5] Podgornik, B., Majdic, F., Leskovšek, V., & Vizintin, J. (2012). Up Edge and Built-Up Layer formation mechanisms in the dry
Improving tribological properties of tool steels through turning of aeronautical aluminium alloys. Wear, 302(1-2),
combination of deep-cryogenic treatment and plasma nitriding. 1209-1218. https://doi.org/10.1016/j.wear.2012.12.001
Wear, 288, 88-93. https://doi.org/10.1016/j.wear.2011.04.001
[6] Meng, F., Tagashira, K., Azuma, R., & Sohma, H. (1994). Role
of eta-carbide precipitations in the wear resistance Authors’ contacts:
improvements of Fe–12Cr–Mo–V–1.4C tool steel by
cryogenic treatment. ISIJ International, 34, 205-210. Dr. sc. Sanja ŠOLĆ, Assistant Professor
https://doi.org/10.2355/isijinternational.34.205 University North, Department of Mechanical Engineering
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of eta-carbide precipitation’s in the wear resistance E-mail: sanja.solic@unin.hr
improvements Fe-12Cr-Mo-V-1,4C tool steel by cryogenic
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treatment. ISIJ International, 34(2), 205-210.
University of Zagreb, Faculty for Mechanical Engineering and Naval Architecture,
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deep-cryogenic treatment on wear resistance of vacuum heat-
treated HSS. Vacuum, 80, 507-518. Dr. sc. Vlado TROPŠA, Associate Professor
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[10] Molinari, A., Pellizzari, M., Gialanella, S., Straffelini, G., &
Stiasny, K. H. (2001). Effect of deep cryogenic treatment on

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ISSN 1846-6168 (Print), ISSN 1848-5588 (Online) Original scientific paper
https://doi.org/10.31803/tg-20190226231838

THE INFLUENCE OF PRINTING, LAMINATION AND HIGH PRESSURE PROCESSING ON SPOT

COLOR CHARACTERISATION

Renata TOMERLIN, Mario TOMIŠA, Damir VUSIĆ

Abstract: The food industry has recognized the important role that multi-layered, flexible packaging materials play and it uses them extensively within the packaging processes.
Trends within food processing and packaging continuously encourage manufacturers to develop new technologies which extend a product’s shelf-life. The samples that were the
subject of research described in this paper are retort stand-up pouches made of multi-layered flexible material, the layers of which have been bonded with a laminating process
that aims to both extend a product’s shelf-life and stability, permitting the final processing of the finished product under aggressive regimes. It is intended that packaging, when
subjected to graphic reproduction and high pressure processing, shall remain unchanged in all aspects, in particular the visual aspect that is the subject of the research. The
samples were printed on polyester film (PET) using a rotogravure printing technique and laminated on aluminum (Al), oriented polyamide (OPA) and finally on inner polypropylene
(PP) layers. The sample was monitored for the Vegeta Blue spot colorimetric difference in the CIE L*a*b* space throughout the individual graphic reproduction phases and the
final high pressure processing (HPP) of the finished product. The goal is to determine the size of the spot color colorimetric difference (∆𝐸𝐸 ∗ ) in relation to the defined formula and
the established standard. On the basis of measured results, guidelines and recommendations for the correction and quality assessment of spot color reproduction throughout the
entire process were defined, with the goal to minimize any deviation to the lowest possible level.

Keywords: CIE L*a*b*; colorimetric difference; food packaging; high pressure processing; spot color

1 INTRODUCTION comply with all legal requirements and regulations to achieve

success on the market [3].
The packaging of a product was originally considered as The composite multi-layer flexible packaging material
anything that held, protected and stored its contents. It has was used to manufacture the samples used in the research
evolved throughout history from its initial role to that of a presented in this paper, which included not only the different
key element and driver of a marketing mix. Simplicity has types of polymeric materials but also a layer of aluminum
led to complexity and, aside from retaining the basic that provides an adequate barrier and adds container strength
functional features, packaging has now acquired a number of for all of the production processes to which the packaging
new attributes. It communicates and is unique in its shape, is shall be subjected. The packaging material is composed as
easily recognizable, uses intelligent materials and colors, follows (Fig. 1):
applies unique coding and is interactive, biodegradable and, • Polyester PET 12 μ
in some instances, edible. All of this and much more make • Aluminum Al 9 μ
up today’s food packaging. Its design and attractiveness draw • Oriented polyamide OPA 15 μ
consumer attention to a shelf and encourage the purchase and • Polypropylene PP 75 μ.
consumption of products [1, 2]. As color and form are the
most recognizable design elements, each retail chain brand The composition of this packaging material is suitable
strives to achieve the spot color standardization that forms for High Pressure Processing (HPP). High pressure
the dominant element of its visual identity. Throughout the processing (HPP) is an industrially tested technology that
packaging process, from its initial inception, i.e. the offers a more natural, environmentally friendly alternative
designer’s idea, through production and final placement on for pasteurization or shelf life extension of a wide range of
the shelf, special attention is paid to the colorimetry and food products [4]. Commercial high pressure and low
reproduction quality of all elements defining the visual temperature methods achieve inactivation of vegetative
design, especially those involving the spot color reproduction microorganisms by subjecting vacuum-sealed food in
defined and permitted within the CIE L*a*b* color space. flexible packaging to treatment at hydrostatic pressures of
The packaging industry is one of the global leaders in 600 MPa (or less) and initial temperatures lower than 40 °C
industrial production and food packaging is the main segment for one to fifteen min. depending upon product application.
within the whole packaging industry. A food product with packaging is subjected to treatment at
Numerous new food packaging products appear on the 300, 400 and 500 MPa pressures for a defined time period of
market every year and face high levels of competition and 5 and 10 minutes. Pressures above 400 MPa at ambient
increased consumer demands. Every food product includes a temperature inactivate the vegetative flora (bacteria, virus,
food packaging system, and this has become an increasingly yeasts, molds and parasites) present in food, extending the
influential factor when a consumer decides to purchase a products shelf life importantly and guaranteeing food safety.
particular product when there is a choice of various brands of High Pressure Processing respects the sensorial and
the same type of the product. Just as with food, food nutritional properties of food, because of the absence of heat
packaging must meet high quality and safety standards and

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treatment, and maintains its original freshness throughout the division as the stiffness of a material depends on the type of
shelf life [5]. polymer. Therefore, for example, PVC (polyvinylchloride)
or cellulose nitrate will already be rigid at 70 – 80 μ, whereas
LD PE (low density polyethylene) will not be rigid even at
Polyester (PET) 300 μ [10].
Printing Ink
Laminate adhesive Polymers are very rarely used in their original form, and
Aluminium (Al)
Laminate adhesive
in order to achieve good characteristics to be a packaging
Oriented polyamide (OPA) material, different additives are added during their
Laminate adhesive
Polypropylene (PP) production to improve their properties. In addition to the
combination of different polymers, multi-layered flexible
packaging is combined with other materials (e.g. paper and
Figure 1 Multi-layered Stand-up Pouch Material aluminum) that aim to increase endurance, packaging
resistance and barrier properties.
2 FLEXIBLE MULTI-LAYERED FOOD PACKAGING Currently, a new EU Directive is being developed, and it
is known as the SUP Directive (Single-Use Plastics). This
Food packaging experienced its greatest expansion and Directive shall also partly cover the packaging materials
flourishing in the second half of the 20th century. This is primarily intended for snack products, beverage industry and
partly due to the development and discovery of new polymer in general all food intended for direct consumption without
materials and partly due to increased food production as a further processing [11]. A great deal of pressure has been
result of population growth, urbanization, lifestyle changes, applied to manufacturers of plastics and polymer materials
female employment and increasingly pronounced hygiene relating to the adequate disposal and recycling of materials
habits [6]. with a view to reducing marine pollution in seas, marinas and
Packaging material is any material from which the environment in general. Regardless of its negative
packaging is made, such as: glass, plastic, paper, cardboard, reputation and poor image, plastic has a number of benefits
wood, metal multi-layered mixed materials and other over other packaging materials and it is impossible to
materials [7]. imagine life without it.
Multi-layered mixed flexible material plays an important Only 1.5% of all oil and gas consumed in Europe is used
role within the packaging material segment. Multi-layered as a raw material for the production of plastic packaging,
packaging is predicted to grow at an annual rate of 4.1%, while 90% is used for heating, transportation and energy
meaning an increase from 27.4 million metric tons in 2017 to production. If food is packaged with other packaging
33.5 million metric tons in 2022. The financial market share materials, the associated energy consumption would be
of flexible packaging material is growing annually by 4.3% doubled and greenhouse gas emissions would be almost
and by 2022 this is expected to amount to 283 billion USD tripled. This would also be accompanied by a 360% increase
[8]. in packaging weight. It is the lightest packaging material.
Historically, polymer materials have only been used as a More than 50% of all European products are packed in plastic
packaging material for a short period of time and, from their that only accounts for 17% of the total packaging weight of
initial mass use in the 1950s onto the present day, their all products on the market. Furthermore, this weight has been
properties have constantly improved, changed and been reduced by 28% over the previous 10 years. Lightweight
enhanced. Packaging materials are almost exclusively made packaging means lighter loads and fewer trucks required to
from plastomers. A considerably smaller amount of duromers deliver the same amount of products, thus reducing energy
and elastomers are used as an auxiliary material for sealing consumption for transportation, CO2 emissions and
lids and fasteners [9]. transportation costs [12].
The polymers most commonly used in plastic packaging From the perspective of companies and consumers
include: (users), packaging must achieve several goals:
• Polyethylene (PE), • Identify a brand,
• Polypropylene (PP), • Contain the product’s description and valid information,
• Styrene homo- and copolymers [polystyrene, (PS), • Facilitate smooth transportation and product protection,
styrene-acrylonitrile (SAN) and acrylonitrile butadiene • Facilitate storage for the consumer and
styrene (ABS), • Enable easy consumption of the product [13].
• Polyvinylchloride (PVC)
• Polyamide (PA) All of this is possible with multi-layer flexible packaging
• Polyethylene terephtalate (PET) and as certain polymer materials provide an excellent printing
• Polycarbonate (PC) [9]. substrate, look extremely attractive on the shelf and offer a
range of options for additional effects, such as various
Usually, these are divided into flexible and rigid lacquers, partial matte or glossy finishing, a metallic effect if
packaging materials. Everything that has a thickness of up to a printed surface is laminated on an aluminum surface
250 μ (0.010 inch) is considered a flexible material or film, without white primer, etc. Additionally, handling, production
and everything thicker is considered a rigid polymer. and transportation of this type of packaging material is
However, in practice, this is not the most effective method of simple and allows for storage in ambient temperatures for an

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 Renata TOMERLIN et al.: THE INFLUENCE OF PRINTING, LAMINATION AND THE HIGH PRESSURE PROCESSING ON SPOT COLOR CHARACTERISATION

extended shelf life, provided of course that the packaging complex and requires the connectivity of designers,
remains hermetically sealed and secured. A relatively new marketing experts, development engineers and specialist
form of packaging on the Croatian market are stand-up expertise from suppliers of certain packaging materials.
pouches made of flexible multi-layered materials, suitable for Primary packaging is in most instances characterized by
sterilization and high pressure processing and practical for applied printing. In order to achieve excellent printing
use and application. Stand-up pouches can take various results, graphical preparation, customized to specific printing
forms, depending on the molding tool on the forming techniques and characteristics, is required. The printing
machine and the staples used, and they can include possible phase is followed by lamination processes, die-cutting
variants such as a sealing strip or laser perforations or forming and sealing the retort stand-up pouch in this case. In
indentations for easier opening. Depending on the addition to the processes listed above, the packaging that is
combination of packaging materials, these may be the subject of this research is also exposed to the processing
transparent or contain an aluminum layer, but the latter are of a finished product, which in this instance means exposure
not suitable for heating in a microwave oven. to high pressure processing during which unwanted changes
The retort stand-up pouches are the actual subject matter to the packaging material can occur, and that manifest in the
of this research. It defines the colorimetric difference of the form of de-lamination of the packaging material, separation
Vegeta Blue spot color in the CIE L*a*b* space applied to the of individual layers or changes in a polymer, which in turn
packaging design to detect the phase of the process that can affect colorimetric difference and subsequently
causes the greatest colorimetric difference in relation to the consumer perception.
defined standard and color formula. When shopping,
customers are inclined to select certain products according to 3.1 Design, Graphic Preparation and Printed Form
their individual habits and memorized characteristics. The Production
main feature of Vegeta branded products is their recognizable
blue color. Vegeta Blue is a color that should be kept within For the purposes of the research presented in this paper,
a strictly defined tolerance range (∆𝐸𝐸 ∗ ≤ 1), regardless of the a design has been applied to the already existing technical
type of packaging material, printing technique or finishing drawing of the retort stand-up pouch produced by the
process). This is not a simple task at all, as it requires Company Aluflexpack Novi from Umag. Packaging design
selecting an adequate supplier that understands the specifics usually begins with a good, clear and detailed brief for the
of the printing technique, its alignment within the graphic agency and the designer. Since it was necessary to apply the
preparation and design process and permanent quality control Vegeta Blue spot color on as large area of the pouch that was
and measurement of colorimetric values within the CIE the subject of this research as possible, the design was
L*a*b* space throughout the entire graphic and technological completed in the Podravka Design Studio and it included the
process. tailoring of an already existing design to new dimensions.
The Brief is usually drafted by the marketing team with
3 RESEARCH METHODOLOGY expert support from development specialists, who mostly
reduce the ideas of designers and marketing into a practicable
This chapter describes the methodology used in this and feasible framework.
research and the impact of the individual phases of the The stand-up pouch constructed from a multi-layered
graphic and technological process on the Vegeta Blue spot packaging material onto which the design was applied has a
colorimetric difference. Standard values for the Vegeta Blue total volume of 500 ml and measures 140×240 mm. The
spot color were prescribed in Podravka Packaging format of the packaging that is the subject of research is part
Development Dpt., coordinated with the supplier. The results of the standard Aluflexpack Novi product range and
of the measurement of the CIE L*a*b* color values and their formatted components of this shape are currently included in
colorimetric difference per processing stages were compared production. In addition to the design, a color measuring atlas
and colorimetric differences were observed compared to the has been applied on the back of the bag, which will be used
defined standard and the set Vegeta Blue spot color formula. in future studies relating to process of colorimetric
The measurement was taken after printing, lamination and difference.
high pressure processing. It indicated the stage at which the The design and graphical preparations were completed
greatest colorimetric difference outside the tolerance area in Adobe Illustrator CC. Color separation was completed in
occurred and whether it could have an impact on consumer Esko ArtPro, Version 16.0.0 in Company Anilox. Separation
perception. for printing was performed by using seven colors (cyan,
The graphical and technological process is divided into magenta, yellow, black, Vegeta Blue, reflex blue and white).
several stages. The first of these is the graphical design stage, A test print was performed on an Epson Stylus Pro WT7900
which in some instances implies solely the application of ink jet printer, which uses a Micro Piezo TFP head for
visual elements to the already existing form and packaging printing. The printer color management software is GMG
material, and in certain situations this may mean designing a RIP and GMG FlexoProof, Ver.5.8.1.312. A test print using
new form mainly in rigid plastic, glass, or metal packaging, digital technology (GMG proof) was performed for quality
which also requires the development of a new label, a shrink control of all design elements. Podravka, which in this
sleeve foil or another final package decoration. In such instance commissioned the design, received the final color
situations, this design process is more time-consuming and separation and digital print, for quality control purposes. A

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 Renata TOMERLIN et al.: THE INFLUENCE OF PRINTING, LAMINATION AND THE HIGH PRESSURE PROCESSING ON SPOT COLOR CHARACTERISATION

signed digital print serves as a guarantee for the packaging robotic arms and are fully automated, replacing human labor
supplier that all is in order and that the next stage of the and they have led to significantly shorter delivery times,
process, namely the engraving of printed forms, can be often no longer than a few days [16].
embarked upon.
Separation was engraved from the application Collage,
Printed image
which was also used for installation and to define the
following parameters: Impression cylinder
• Lineature, (70 L/cm – 101 L/cm, depends on color),
• Individual separation angles, (33° – 60°, depends on the
color),
• Tool angle, (110° – 130°, depends on the color), Substrate
• Reproduction curve. Plate
Doctor blade
Preliminary prepared cylinders were then engraved on Plate
electronic engraving machines. The engraving was cylinder
performed on an Ohio Gravure Tec. Inc. USA, Gravostar Printing ink
Spectrum Engraving Machine. The process was tailored to
the parameters of the selected substrate and machine on Figure 2 Rotogravure Printing Schematic [17]
which the printing was performed. In order for the print
cylinders to be sufficiently durable to withstand printing on Aside from the high prices of the printing forms,
printing machines, they were finally processed with hard rotogravure printing is also known for evaporation ink
chrome plating, where a protective layer of chromium, finishing. Most printing that utilizes this technique involves
several micro millimeters thick, was applied. Final quality inks based on organic solvents. The vapors from organic
control was performed by a visual inspection of the finished solvents are harmful to human health and highly flammable.
printed forms and the pattern was printed on a test print For these reasons, the plants and facilities where rotogravure
machine utilizing the original inks and consumer substrate printing machines are used require special construction and
(PET 12 μ) at the Aluflexpack Novi Print Shop by simulating safety measures [14]. Companies operating within the EU are
the parameters of the printing machine. A test print was subject to stringent legislation and must be equipped with
performed on a manually processed printing press. The test special types of air purification and solvent recovery devices.
print, when obtained as described above, showed if there The Aluflexpack Novi Print Shop in Umag printed
were any visible defects and if any corrections on print forms design samples on the Schiavi Pulsar Printing Machine, 10
were necessary. The test print with engraved print forms was group, 1.240 mm wide with a maximum speed of 350 m/min,
performed on Rotogravure Proofing Press, a test print utilizing a rotogravure printing technique on transparent, 12
machine produced by JM Heaford of the UK, on a HA μ thick polyester (PET). Aluflexpack Novi utilizes a cutting
3500×1800 (Fixed Drum / Hydraulic Rotation) Model. edge solvent recovery plant and has been awarded the BRC
(the British Retail Consortium) and ISO (the International
3.2 Printing and Finishing Organisation for Standardisation) production certification.
Siegwerk printing inks (thermal-resistant ink),
The samples that are the subject of this paper have been specifically intended for printing packaging that can later be
printed by using the rotogravure printing technique. processed by various methods applied to finished products,
Rotogravure printing is a direct, intaglio printing technique. were used. Resistances of this ink series are archived by
The print face is hollowed out in its printed form and the using completely resistant pigments according to ISO 2836.
blank spaces are foremost [14]. The printing ink is applied on The printed samples were measured for the values of Vegeta
the entire print form during printing and later, a doctor blade Blue and were compared with the set standard values and pre-
removes the printing ink from the blank spaces (Fig. 2). By defined color formula. After the printing phase was
pressing the printing form onto the substrate, the printing ink completed, the laminating process was performed on the
is transferred to the substrate. The printing surface of the PET Rotomec Rotoconvert Machine with three unwinders (a
foil should be treated to be suitable for printing, which has a triplex in a single pass) 1.230 mm wide, with a maximum
significant influence on surface tension and enables the ink speed of 300 m/min. A Henkel agent and a catalyst were used
to connect with the printing substrate [15]. for lamination. A flexible retort stand-up pouch consists of
This printing technique allows the reproduction of very four different materials: PET, Al, OPA and PP. After
small details, small font-sized text, excellent photographs lamination, each material has to pass though the cross-linking
and product views. The usual perception of rotogravure of materials and solvent evaporation phase which aim to
printing within the printing industry is that it is used in the eliminate the problem of residual odor within the packaging
printing of top class brand packaging which must be high- material and any de-lamination and migration problems. The
quality. Quality remains the main feature of the printing Totani BH-60DLLS machine was used to form, seal on three
technology, but in recent years, the producers of printing sides (laterally and on the bottom) and die-cut the stand-up
forms, i.e. engraving companies, have sought to reduce costs pouches, operating at a maximum speed of 1.000
and automate the process. New, fast engraving heads use pouches/min.

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3.3 High Pressure Processing (HPP) defined at what stage in the process and under which
processing regimes, the greatest colorimetric difference
The processes that may cause unnecessary changes in the occurred and what the most significant differences within the
packaging’s properties and appearance do not always end CIE L*a*b* color space were. The average colorimetric
upon the completion of the graphical and technological difference for each phase was defined in the statistical
process. The packaging, as an integral part of the product, is analysis of the measured values and it was expressed by
subject to various food processing regimes, the aggressive applying the method of the median mean. Parallel curves
parameters which can affect the packaging material’s were also shown after each measurement stage
properties. demonstrating the colorimetric difference values compared
The application of food high pressure processing in the to the set color (Figs. 4 and 5).
food industry has developed as an alternative to conventional The measurement was performed on three standard light
thermal processes, such as pasteurization and sterilization, sources: D65./10°, A.../10° and F11./10°. Aluflexpack
aiming to achieve a microbiologically safe product that does Novi’s Print Shop had previously recorded the CIE L*a*b*
not undergo any sensory, physical or nutritional value Vegeta Blue spot color values that are the subject of the
changes. research and the defined formula. For the purposes of this
High Pressure Processing is a cold pasteurization process research, the color formula was to a lesser extent modified in
in which the final packaged product is exposed in a given its composition and it did not use the original values.
chamber to high isostatic pressure (300–600 MPa / 43.500– The following standard measuring values were set for
87.000 psi), which is applied by water (Fig. 3) [18]. Vegeta Blue under three different light sources:

Table 1 Standard Colorimetric values for the Vegeta Blue color

Product loading Vessel Pre-Filling
Light source L* a* b*
D65./10° 52.44 −25.05 −33.41
A.../10° 46.06 −31.96 −45.96
Low F11./10° 46.62 −16.28 −41.82
Water Tank
Pressure
Product unloading Pressurizing Following the measurement and evaluation of all
samples, comparisons of deviations for each process phase
Processed High High
Pressure Pressure
were made. The largest colorimetric difference of the Vegeta
Batch
Figure 3 High Pressure Processing [5] Blue spot color appeared after the lamination phase.
Measurement results were subjected to a statistical analysis
4 MEASUREMENT RESULTS and expressed as a median mean which represented the center
of mass for the set of 25 pouch samples for printing and
The evaluation of the measured samples within this lamination and 24 for the high pressure processing stage.
research was performed on 25 samples for the printing and The measured values were obtained by using the
lamination, and on 24 samples for high pressure processing following formula:
stages. The total quantity of produced samples was 1000
pieces. High pressure processing was carried out at the ∆𝐿𝐿 2 ∆𝐶𝐶 2 ∆𝐻𝐻 2
∆𝐸𝐸𝐶𝐶𝐶𝐶𝐶𝐶 = �� � + � � + � � (1)
University of Zagreb’s Faculty of Food Technology and 𝑙𝑙𝑙𝑙𝐿𝐿 𝑐𝑐𝑐𝑐𝐶𝐶 𝑆𝑆𝐻𝐻
Biotechnology, using a 2 L volume device manufactured by
the Stansted Fluid Power. It applied pressures of 300, 400 and No color tolerance system is perfect, but CMC and
500 MPa for a defined period of 5 and 10 minutes. The CIE94 equations best represent the color differences in the
processing temperature remained constant at 22 ± 1 °C. The way our eyes see them (Tab. 2) [20].
pressure rising rate was set at 5 MPa/s and the release at a
maximum of 20 MPa/s. Four samples were processed in each Table 2 Colorimetric Difference Evaluation Criteria for the Measured Colors
Tolerance Method Matching with Visual Perception (%)
of the pressure and temperature regimes stated above (300, CIELAB 75 %
400 and 500 MPa, during 5 and 10 minutes), totaling 24 CIELCH 85 %
samples. CIECMC 95 %
Changes in colorimetric values were monitored
throughout the printing phase by using a measuring device Table 3 Average Colorimetric Difference Values for the Vegeta Blue spot color
utilizing the standard formula with the CIE L*a*b* Colorimetric
Stage of the process Source of light
difference CMC2:1
colorimetric values for the Vegeta Blue spot color. The color D65./10° 0.23
was measured with a Hunter Associates Lab. Inc. Device, Printing A.../10° 0.23
Type: ColorQuest XE, in Aluflexpack Novi’s Print Shop. F11./10° 0.30
The device was calibrated to accord with the ISO/IEC D65./10° 1.56
17025:2005 and BS EN ISO 9001:2000 Standards. By Lamination A.../10° 1.71
F11./10° 1.43
measuring the samples after each process stage, starting with D65./10° 1.94
printing, the influence of each individual phase on CIE L*a*b* HPP A.../10° 2.28
components in the color space was determined. It was F11./10° 2.10

222 TECHNICAL JOURNAL 13, 3(2019), 218-225

 Renata TOMERLIN et al.: THE INFLUENCE OF PRINTING, LAMINATION AND THE HIGH PRESSURE PROCESSING ON SPOT COLOR CHARACTERISATION

The presented Figs. 4 and 5 show the spectral curves of packaging manufacturers and their specific features (printing
the measured Vegeta Blue spot color regarding the performed inks, machine type, substrate, lamination agents, varnishing
stage of the process. The right part of the picture shows the L etc.), the challenge of maintaining color uniformity within
diagram with two wavelengths of color in two phases and the the CIE L*a*b* space is sometimes insurmountable. The
ab diagram shows the color difference between the two colorimetric values on a multi-layer flexible packaging
phases. The colorimetric difference after printing is within containing aluminum and on the packaging containing only
the tolerance limits and amounts to D65./10° light source transparent polymer materials are not identical. To achieve
CMC2:1 = 0.23. After lamination, a greater colorimetric the identical print, which would mean that the spot color is
difference occurred, the color surpassed the determined within the tolerance area, it is necessary to redefine the spot
tolerance range and the colorimetric difference under the color input formula for every substrate. This, of course,
same conditions equaled to D65./10° CMC2:1 = 1.56 (Fig. makes the process more complicated and more expensive for
4). After high pressure processing, an even higher print shops, but for the manufacturers of brands that are
colorimetric difference of Vegeta Blue occurred and the recognizable by their specific, protected color, the goals is to
average value on the measured samples equaled to D65./10° maintain identical colorimetric values. Specific features of
CMC2:1= 1.94. With lamination, Vegeta Blue became darker individual packaging materials require that the maximum
and crossed into the area of yellow-red. This clearly shows allowed tolerance area and the standard colorimetric values
that HPP also influences the Vegeta Blue spot color for the spot color be defined. During the measuring and
deviations. evaluation of samples, it was noticed that a rather small
deviation of the Vegeta Blue spot color, which occurred after
lamination (ΔE = 1.56), was more visible than greater
Printing
deviations of some other colors. After high pressure
Lamination processing, according to the measured values, Vegeta Blue
1
was darker (Fig. 5).
Օ D65./10Օ 1.56
X A.../10Օ 1.71
ΔF11./10Օ 1,43 5 CONCLUSION

In order to achieve the desired final effect on the

graphical and technological process used for the
manufacturing of packaging and marketing of an on-shelf
product that attracts customers, every company is faced with
a long, complex and well-managed process. It is necessary to
define the packaging material’s type and composition for
Figure 4 Printing vs Lamination
every product, which depends on the product’s properties,
desired shelf life, production lines used for packaging,
handling and method of use in addition to a whole range of
Printing other factors. Once the material type has been defined, it is
Lamination
High Pressure Processing (HPP) also necessary, based on other parameters, to define the
1 2
printing technique which will be used in the printing of
Օ D65./10Օ 1.56 1.94 packaging. The choice of printing techniques is largely
X A.../10Օ 1.71 2.28
ΔF11./10Օ 1.43 2.10 dependent on the price, volume of the packaging ordered,
target quality, further processing of the completed product,
etc. Once the printing technique, the packaging material and
the print shop that will produce the packaging have been
defined, all input parameters have to be agreed upon: the
color, separation and allowed colorimetric difference
tolerance. If more parameters are defined at the very
beginning of the graphical and technological process, the
chance of an error and undesired results is reduced to a
Figure 5 Print vs Lamination vs High Pressure Processing (HPP) minimum. For printing, it is recommended to select a
packaging manufacturer who applies a standardized and
The unacceptable colorimetric difference occurs after the controlled process, which largely facilitates monitoring of
lamination process. By laminating the transparent polyester packaging through each of the stages and results in a
layer (PET) onto the aluminum surface, a change occurs in colorimetric difference not exceeding the tolerance area
all parts of the CIE L*a*b* color system. The problem that agreed between the ordering party and the packaging
arises when the transparent polyester is laminated onto the manufacturer. Standardization and monitoring of all stages of
aluminum surface is inconsistent graphic reproduction, such a process is the only way packaging can be produced
which could be prevented by adjustments to the color recipe. within the defined area of a tolerated colorimetric difference,
Food packaging is made of different packaging materials and and meet the goal of the acceptable difference generally
with different printing techniques. Together with different invisible to consumers’ eyes.

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 Renata TOMERLIN et al.: THE INFLUENCE OF PRINTING, LAMINATION AND THE HIGH PRESSURE PROCESSING ON SPOT COLOR CHARACTERISATION

Increasingly aware and informed consumers now have involvement of several different teams and experts is also
numerous requirements which they expect from packaging, necessary in order to prevent any problems on production
and these requirements have to be met. Packaging no longer lines or later during the handling and processing of a product.
has only a protective or storage function. It is a ‘silent seller’ The fact that industrial production is not the same as the small
on the shelf, contributing to distinction, increasing manufacturing plants of family proprietorships should not be
recognition and is interactive, easy to handle and provides a forgotten. Industry seeks to eliminate manual work,
range of additional benefits such as laser perforation, re- machines have high capacities and under ideal conditions, the
sealable options, microwave heating or direct consumption. output control of the packaging manufacturer becomes the
It must comply with the guidelines on sustainable input control of the ordering party, but all this presumes
development, environmental protection, etc. At first sight, error-free packaging items. The shelves in shops today are
what the consumer ranks the highest is the color perception overcrowded, full of special offer packaging and novelties. It
and an emotional link with the brand. In order to achieve is impossible to determine which of the packaging properties
attractiveness in a shop and draw the initial attention of the is the most important for the consumer, whether the
consumer, which only lasts a few seconds, a consumer makes his/her decision consciously or based on
multidisciplinary approach and a highly complex emotions linked to a familiar brand. The task for every
implementation process are necessary. manufacturer of recognized trademarked products is to
The goal of the research presented in this paper was to achieve uniformity of spot color on different packaging
determine the value of the Vegeta Blue spot colorimetric materials, with different printing techniques and with
difference that appears on packaging during printing, different suppliers. The parameters which influence changes
processing and high pressure processing of the completed in spot colors are the subject of this paper and they are really
product. The Vegeta Blue spot color was measured after these numerous in products marketed in several different types of
stages and compared with the set standard in order to achieve packaging material. There is a difference between printing on
better qualitative properties for the final product and improve a mono material with a white background and a multi-layer
its attractiveness on the shelf. Based on the measurement flexible material composed with aluminum or metallized foil.
results, the process stages that provide the highest impact on For the Vegeta Blue spot color, just like for all other world
color deviation were determined. The formula for the Vegeta famous brands, the intended goal is to reach colorimetric
Blue spot color with its allowed tolerance area (ΔE ≤ 1) was values that will be within the desired tolerance area. There
defined as the measurement starting point. are several software solutions which will facilitate the
The results were the measured values for the Vegeta Blue standardization process, but every ordering party should be
spot color. High pressure processing (HPP) causes deviations aware that it is impossible to achieve laboratory conditions in
in the CIE L*a*b* values of spot color and it increases the production plant. It is easy to manage and control
deviation that is a result of the lamination process. The standardization with one supplier, on a defined type of
measurement has shown that the spot colorimetric difference packaging material, with a defined type of printing inks, the
that occurs during the processing phase is lower than the lamination agent that is always the same, printing forms
difference that occurs during the lamination stage. During made with identical parameters and always by the same
high pressure processing, a change in process colors was also manufacturer. All this cannot guarantee a perfect result, but
identified (cyan, magenta, yellow and black), in the colors of any colorimetric difference in such cases has been reduced to
the dish presented as a part of the design. The changes to a minimum. The reality of food companies is unfortunately
process colors were not the subject of the research presented slightly different from the described ideal conditions. All
in this paper, but the Company Anilox measured these values manufacturers, for a variety of reasons, use the services of
against the atlas of the colors applied, specifically to enable several packaging manufacturers and in such situations,
further research. It is exactly the process colors for which standardization, and subsequently the control of colorimetric
deviations resulting from sterilization and high pressure values and other packaging characteristics, become more
processing can be prevented during the graphic preparation complex and difficult in practice.
and print form design stages. The relating research provides a good basis for further
This Paper has defined the Vegeta Blue spot color value research in the area of process color and other packaging
of the colorimetric difference in the CIE L*a*b* color space material deviations, within the area of printing techniques
for printing, lamination and HPP stages. This paper also and processing procedures and other processing methods
proposes guidelines to achieve colorimetric difference within applied to a finished food product.
the previously defined tolerance ranges for individual colors,
and determines those parts of the technological process that 6 REFERENCES
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[3] Young, T. K., Byungjin, M., & Kyung, W. K. (2014) General Authors' contacts:
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ISSN 1846-6168 (Print), ISSN 1848-5588 (Online) Original scientific paper
https://doi.org/10.31803/tg-20190328155758

ADVANTAGES AND DISADVANTAGES OF RAMAN SPECTROSCOPY IN TESTING PAPER

BANKNOTES

Gordana JAUKOVIĆ

Abstract: This paper presents advantages and disadvantages of Raman spectroscopy when used for testing banknotes, i.e. in case study I, 1 and 5 dinars banknotes from a
private collection dating from 1876 of numismatic value were analyzed, and in case study II, 1000 dinars banknote from circulation together with its counterfeit. In both cases
banknotes were analyzed by using Raman spectrometer DXR Raman microscope at the Faculty of Physical Chemistry, with a laser of wave-length 780 nm at 12 mW of power.
Specters were recorded under microscope using 50X lens in a range 1800-60 cm-1. Analyses from case study I on both specimens showed spectrum characteristic for fluorescence
appearance, therefore intensive signal of fluorescence covered Raman signal. In case study II, it was established that Raman spectroscopy can reliably detect a counterfeit
banknote. Research, comparisons and analyses regarding original and counterfeit 1000 dinars note were performed on red banknote surfaces.

Keywords: banknotes counterfeiting; forensics; numismatics; printing inks; protective elements; Raman spectroscopy; spectrum

1 INTRODUCTION 2 EXPERIMENTAL PART

2.1 Materials and Methods
The need for multidisciplinary examination of objects
with cultural-historic value emerged in order to preserve and This paper is focused on examination of pigments used
protect them from counterfeiting. In this paper, we are in banknotes to obtain characteristic Raman spectra that serve
focused on historical banknotes and banknotes form for the authenticity assessment. For the first time in the
circulation, as an issue of importance for numismatic Republic of Serbia, in 2015, the Raman spectroscopy was
museums, private collectors and researchers responsible for used to evaluate the applicability of this method for the
the care of numismatic collections. The scientific detection analysis of banknotes. The results of the study were applied
of forgeries is an important task for numismatic researchers in two case studies; first case study was conducted on two
around the world since they are responsible for determining specimens of historical banknotes from 1876, and the other
the authenticity as well as the historical and monetary value examination was done in the second case study on a banknote
of their collections. Complexity of this issue is further from circulation and its counterfeit. Measurements were
increased by influence of time that increases transformation performed at Laboratory for micro-Raman spectroscopy at
and degradation of pigments and binders. Banknotes and the Faculty for Physical Chemistry in Belgrade. Banknotes
postage stamps have complex composition; thus, several were examined by Raman spectrometer DXR Raman
methods should be used for their identification [1, 2]. One of microscope (Thermo Scientific) with a laser of wave-length
the approaches used in identification of materials is physical- 780 nm at 12 mW of power. Spectra were recorded under
chemical analysis, such as Raman spectroscopy. Raman microscope using 50× lenses in a range 1800-60 cm−1.
spectroscopy can give qualitative, quantitative and structural During recording, a 10 s exposition with 10 repetitions was
information on different materials [3]. Numerous studies used.
have been devoted to evaluating the efficiency of several
analytical techniques for the detection of forgeries of 2.2 Case Study I – 1 Dinar and 5 Dinars Banknotes of Year
banknotes form circulation [3˗5]. Gaining insight into 1876 – Money of Central Treasury: A Historical Money
microchemical and microphysical nature of banknotes is Description
invaluable for clarifying issues regarding the source of
materials, production techniques, exchange and trade, and According to archive documents, specimens of
many other social cultural elements. Since multidisciplinary banknotes from 1876 were printed in State Printing Works in
approach in examining banknotes is at its beginnings, the Belgrade, but the paper was bought from supplier Le Franc
results of this and other similar research could contribute in and imported from Paris. Archive documents indicate that
finding the best solution for framework of the future expected results should refer to spectra of "Berlin" blue,
comprehensive database of cultural heritage (library of known in materials technology literature under the official
pigments and materials used in the production of banknotes) name "Prussian blue" or "Paris blue" [6]. Paper surface was
[1˗5]. covered with yellowish net – impregnation [6, 7]. Dinar
banknotes from the end of the 19th century had watermark
containing figures and words denoting value, which is visible
in Fig. 1a) and 1b). Law articles regarding punishments for
counterfeiters were printed in textual form.

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 Gordana JAUKOVIĆ: ADVANTAGES AND DISADVANTAGES OF RAMAN SPECTROSCOPY IN TESTING PAPER BANKNOTES

microscope (Thermo Scientific) with a laser of wave-length

780 nm at 12 mW of power. Spectra were recorded under
microscope using 50× lens in the range 1800-60 cm−1. During
recording a 10s exposition with 10 repetitions was used.
Spectra were corrected regarding fluorescence through the
use of fifth degree polynomial in a software package.
a) b)
Figure 1 Watermark as a protective element in denominations of: a) 1 dinar and b)
5 dinars from 1876. Central part has figures "1" and "5", with word "DINAR" printed
in Cyrillic capital letters. 1

2.2.1 Evaluation of Banknotes by Raman Spectroscopy –

Denominations of 1 and 5 Dinars from 1876 2
4
Banknotes in denominations of 1 and 5 dinars from 1876
3
Fig. 1a) and 1b) were evaluated by Raman spectrometer DXR
Raman microscope (Thermo Scientific) with a laser of wave-
length 780 nm at 12 mW of power. Spectra were recorded Figure 3 Marked regions of 1000 dinar banknote where Raman spectra were
under microscope using 50× lens in the range 1800-60 cm−1. recorded
During recording, a 10 s exposition with 10 repetitions was
used. Spectra were corrected regarding fluorescence through
use of fifth degree polynomial in a software package. In case
of banknote specimens from 1876 it was impossible to
identify certain pigments used in banknote manufacturing
due to pronounced fluorescence. The spectrum characteristic
for appearance of fluorescence was noticeable in both
specimens, regardless of recorded point (both in clear paper
and pigment itself) and variations of experiment conditions.
The fluorescence originates (Fig. 2) from paper used for
banknote manufacturing, and it was visible due to laser
radiation from visible part of electromagnetic spectrum. That
makes the intensive signal of fluorescence cover Raman
signal, disabling pigment analysis with DXR Raman
microscope. Therefore, to get reliable information, it would
be necessary to implement different methods such as FTIR
spectroscopy, since it is also a noninvasive method [4].

Figure 4 Raman spectra from region 1 on original and counterfeit banknote

Spectra from region 1 recorded in original and

counterfeit banknote are presented in Fig. 4. Spectrum a) in
original banknote based on stripes 1521, 1334, 1141, 745,
678 and 482 cm−1 can be attributed to spectrum of blue
phthalocyanic pigment, since during recording with 780 nm
laser it shows resonant effect. Resonant amplification of
intensity of that pigment can cause masking stripes of other,
possibly present pigments [8]. Spectra b) and c) in original
banknote show intensive stripe at 143 cm−1 originating from
Figure 2 Pronounced fluorescence on samples of 1- and 5-dinars banknotes from
TiO2 in anatase form. Besides that, noticeable stripe in
1876
spectrum b) is stripe at 1597 cm−1 that could arise from
2.3 Case Study II – Circulation Banknotes, 1000 Dinars vibrations of aromatic rings of orange diazo pigments of
Denomination and Its Counterfeit pyrazoline [9, 10]. In the same region of counterfeit banknote
the spectrum received was of green phthalocyanic pigment,
Circulation banknotes, 1000 dinars denomination (Fig. spectrum a), with most intensive stripes at 1544, 1338 and
3) and its counterfeit, were evaluated in same conditions as 748 cm−1 [11]. Unlike original banknote, counterfeit
in the first case study by Raman spectrometer DXR Raman produced stripes of cellulose, i.e. of paper, spectrum b). In

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 Gordana JAUKOVIĆ: ADVANTAGES AND DISADVANTAGES OF RAMAN SPECTROSCOPY IN TESTING PAPER BANKNOTES

spectrum c) of counterfeit banknote most intensive stripe In region 3 of original banknote (Fig. 6) spectrum that
noticeable is at 1085 cm−1 arising from white pigment – chalk would enable identification of pigments was not received,
[11]. while counterfeit banknote produced very good spectrum of
During recording of spectrum in region 2 of original blue phthalocyanic pigment.
banknote (Fig. 5) intensive fluorescence occurred, so just a In region 4 of original banknote (Fig. 7) TiO2 was
single spectrum was recorded (after correction) with identified in anatase form, spectrum a), naphthol red pigment
noticeable weak stripes at 1586, 1560 and 1364 cm−1 of red (alizarin), spectrum b), while spectrum c) corresponds to blue
pigment (alizarin) [8]. In the same region of counterfeit phthalocyanic pigment. From counterfeit banknote received
banknote green phthalocyanic pigment, spectrum a), was was spectrum of green phthalocyanic pigment, with
identified as well as chalk, spectrum b). pronounced stripes of cellulose at 1120 and 1090 cm−1.

3 CONCLUSION

The results of the measurements are given in Figs. 2, 4,

5, 6 and 7. Our measurements successfully confirmed that
there are advantages and disadvantages in examining
banknotes with the Raman spectroscopy. Within the first case
study, the analyzed specimens of historical banknotes gave
unsuccessful measurements due to the spectrum
characteristics. In addition, appearance of fluorescence was
noticeable in both samples due to the yellowish
impregnation. Recommendation for further analysis is
employment of other noninvasive techniques such as FTIR.
In the examination of specimens in the second case study we
concluded that the Raman spectroscopy is a successful and
Figure 5 Raman spectra of region 2 in original and counterfeit banknote easily obtained method applicable in forensic evaluation of
circulating banknotes and counterfeits.

Acknowledgement

Many thanks to Dr Danica Bajuk-Bogdanović, research

associate at the Faculty of Physical Chemistry, for assistance
in recording and interpreting Raman spectra. This research
was conducted in 2015 within the curriculum of PhD studies
Figure 6 Raman spectra of region 3 in original and counterfeit banknote History and Philosophy of Science and Technology at the
University of Belgrade.

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and counterfeit banknotes using Raman spectroscopy and PLS-
DA with uncertainty estimation. Microchemical Journal, 109,
170-177. https://doi.org/10.1016/j.microc.2012.03.006
[9] Nadim, C. S., Zumbuehl, S., Delavy, F., Fritsch, A., Kuehnen,
R. (2009). Synthetic organic pigments of the 20th and 21st
century relevant to artist’s paints: Raman spectra reference
collection. Spectrochimica Acta Part A, 73, 505-524.
https://doi.org/10.1016/j.saa.2008.11.029
[10] Schulte, F., Brzezinka, K.-W., Lutzenberger, K., Stege, H., &
Panne, U. (2008). Raman spectroscopy of synthetic organic
pigments used in 20th century works of art. J. Raman Spectrosc.
39, 1455-1463. https://doi.org/10.1002/jrs.2021
[11] Caggiani, M. C., Cosentino, A., Mangone, A. (2016). Pigments
Checker version 3.0, a handy set for conservation scientists: A
free online Raman spectra database. Microchemical Journal,
129, 123-132. https://doi.org/10.1016/j.microc.2016.06.020

Author’s contact:

Gordana JAUKOVIĆ, PhD student of Belgrade University,

Senior Associate, National Bank of Serbia,
Communication Department, Unit for Exhibitions and Education,
12 Kralja Petra St, 11 000 Beograd, Serbia
gordana.jaukovic@nbs.rs
gordana.jaukovic@gmail.com

TEHNIČKI GLASNIK 13, 3(2019), 226-229 229

ISSN 1846-6168 (Print), ISSN 1848-5588 (Online) Preliminary communication
https://doi.org/10.31803/tg-20190817135410

VORTEX COOLED AIR TURNING OF INDUCTION-HARDENED RACEWAY ON THE WIND

TURBINE-BEARING RING

Mladen BOŠNJAKOVIĆ, Olivera MAGLIĆ, Dragomir MOŠKUN, Zoran CRNAC

Abstract: In the turning process of hard materials with CBN cutting inserts, metalworking fluid is not advisable as it results in poorer quality of finished surface and shortening of
the tool life. Dry machining, otherwise, develops excessive heat, residual stresses in the workpiece material due to thermal stress, and therefore causes possible problems of
achieving tolerances on larger workpieces. During the dry turning of induction hardened raceway on the wind turbine-bearing ring of 1500 mm in diameter, problems with achieving
tolerances occurred. The vortex-cooled air implementation during turning resulted in achieving designing tolerances of the workpiece, with better surface roughness and with less
tool wear. The result was 50% lower cost of cutting inserts and small operating costs associated with air consumption. The vortex-cooled air implementation makes it possible to
extend the tool life of CBN cutting inserts and thus higher cost-effectiveness of machining.

Keywords: cost-effectiveness of machining; turning; vortex-cooled air

1 INTRODUCTION Cutting fluids could be replaced by cold compressed air,

to cool and to remove chips from cutting area. Compared to
The industrial world is slowly moving toward dry cutting fluids, this technique significantly cut production
machining as the technology of the future. Development of costs, and it is not harmful to the environment and human
environmental awareness, concern for human health, and law health [7]. Applying cold air to the tool interface of these
regulations force industrial production to avoid using cutting modern tooltip will also extend their tool life reducing the
fluids and turn to develop and improvement of dry cost of metal-cutting.
machining. With regard to the workpiece type, implementing dry
Drivers for the implementation of a dry cutting are in machining instead of conventional wet machining will get
particular companies with series production in the field of savings of total costs for 17%. This will happen due to the
automobile manufacturers and their suppliers. But the elimination of cutting fluids, cleaning of the machine,
transformation from wet to dry cutting comes along with maintenance and removing cutting fluids [8].
major problems, strong heating of the workpiece during dry Cho and other investigated influence of cold compressed
cutting, higher tool wear, and finally, thermally caused air at −4 °C to −25 °C pressure of 4 bar and showed that
dimension and form deviations [1]. F. Klocke et al. lowering the air temperature will increase surface quality and
developed a model to predict and compensate the decrease residual stress [9].
thermoelastic workpiece deformation [2]. Cooling with cold compressed air is usually performed
Problems arising from the dry cutting process are by vortex tube.
specific to each process and each combination of tool- The vortex tube is known as the Ranque-Hilsch vortex
workpiece materials. To apply dry cutting, the most tube. It is a device that enables separation of hot and cold air
significant changes in the design of manufacturing systems during the flow of compressed air through an inlet nozzle
are linked to cooling, additional equipment and adaptation of tangential to the vortex chamber. Vortex tube was invented
cutting processes to the new restrictions [3]. Requirements in 1933 by a French metallurgist and physicist Georges
for high dimensional accuracy are still a limiting factor for Ranque and improved by German physicist Rudolf Hilsch.
the application of dry machining. The cooling during the Although the basic work principle of the vortex tube is
process is necessary when there is strong adhesion between known, details of the process are still investigated, recently
the tool and workpiece or when tool wears is too intensive, with Computational fluid dynamics (CFD) simulation [10].
or when it is not possible to control the thermal deformation Besides that, the influence of the geometry of the vortex tube
of the workpiece. to fluid stream parameters is also investigated.
A necessary precondition for implementation of dry The vortex tube is a simple device, which does not have
machining is an acceptable substitution of the functions of moving parts and simultaneously produces a hot and cold
cooling and lubricating agents. In first investigations, regular stream of air at two ends from the source of compressed air.
compressed air was used, and its performance was inferior to It consists of a long tube that has a tangential nozzle at
water and oil [4]. Implementation of cold compressed air one end and valve at the other end, as shown in Fig. 1.
obtained better results. Nandy and others had shown that the Compressed air is introduced in the tube by a tangential
use of a cold compressed air maximizes tool lifetime and nozzle that creates a vortex of the inlet air stream (in some
machining productivity, giving the opportunity to use higher cases over million rounds per minute) [11].
machining parameters related to dry machining [5, 6].

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 Mladen BOŠNJAKOVIĆ et al.: VORTEX COOLED AIR TURNING OF INDUCTION-HARDENED RACEWAY ON THE WIND TURBINE-BEARING RING

Air vortex is moving toward an adjustable valve at the hot you control the "cold fraction", which is the percentage of the
end that controls the volume of the airflow and the total input of compressed air that exits the cold end of the
temperature existing at the cold end. By adjusting the valve, Vortex Tube.

Figure 1 Scheme presenting Ranque-Hilsch tube

The adjustable valve leaks smaller part of the swirling air Machining of material 42CrMo4 was experimentally
along the wall of the tube (20% to 40%), and central part of investigated by Sutter et al [13]. They determined that at
air vortex is directed in the opposite direction creating inner cutting speed around 20 m/s, the temperature measured near
vortex through outer air vortex. Inner vortex transfers heat to the tool-chip interface achieved a maximal value of 870 °C
outer vortex near the wall and, with a significant decrease of for 42CrMo4. The increase of the cutting speed from 10 m/s
temperature, air exits on the cold end of the tube. Outer to 65 m/s raises continuously the chips’ temperature and
vortex near tube wall exits on the opposite end with a influence the location of the maximal temperature.
temperature higher than the temperature of inlet air. Vortex
tube has many possible industrial applications and could be Table 1 Workpiece basic data
used as a cooling device at CNC machines, in refrigerators, Description Values
Item name Inner ring
heating processes, etc. High applicability of vortex tube is Number of workpieces 27
based on its simplicity, compactness and the fact that the Material designation 42CrMo4V
system has a small mass and works in quiet mode. These Rolled ring, hardened and tempered at 800-
Material condition
tubes do not have moving parts, so they do not break or wear 900 MPa
which makes them simple for maintenance. Final machining of induction hardened
Machining type
raceway with 56 HRC ±2 HRC for ball ∅50
Application of cold air will decrease the temperature at
the cutting area during machining; it will decrease the
temperature of tool, chip and workpiece due to intense heat
removal by convection which emphasizes the importance of
convection coefficient for tool temperature modelling.
Convection coefficient for cutting fluids based on water is in
the range from 103 to 104 W/(m2K). Convection coefficient
for cold air was investigated for the first time by Liu and
Chou [12] and in simulation, it has values in range 50-5000
W/(m2K), while in the experiment it is about 160 W/(m2K)
with applied air of temperature up to −15 °C and 860
W/(m2K) for cooling with air with temperature up to −25 °C.

2 MATERIAL AND METHODS

2.1 Problem Definition
Figure 2 Scheme of inner ring
Example of machining without using cutting fluid is
turning on a big vertical turning machine with maximal The dimension of the critical machined surface is
diameter 4270 mm with an embedded CNC control system. measured by stick micrometer on balls ∅50 which are set at
Although the machine is equipped with an emulsion cooling 180º on a rolling raceway.
system, the manufacturer of the CBN (cubic boron nitride) Two persons perform measuring – a worker on the machine
inserts recommends turning without coolant. In accordance and inspector. Results are recorded in the control list due to
with this recommendation, induction hardened ring raceways mounting ring in the axial bearing.
for big axial bearings were performed. The problem that was noticed 24 hours after the final
Final machining of hardened raceway bearing was tried machining is the change in measure over balls for 0.1 mm to
with PCBN (polycrystalline cubic boron nitride) insert 0.2 mm which make impossible to mount two rings in the
without emulsion cooling because due to high temperature in axial bearing. Rings had to be re-machined.
cutting area cooling liquid evaporated and the insert would Requirements to the technology department were to find a
be damaged. solution for how to:

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 Mladen BOŠNJAKOVIĆ et al.: VORTEX COOLED AIR TURNING OF INDUCTION-HARDENED RACEWAY ON THE WIND TURBINE-BEARING RING

• decrease stress in the ring which is caused by thermal Optimal machining parameters according to the
expansion due to higher ring temperatures during recommendations from literature presents a combination of
machining, low feed rate and low depth of cut with higher cutting speed,
• perform dimensions in given tolerances, which is beneficial for reducing cutting temperatures,
• decrease tool costs. machining force and surface roughness (Tab. 4).

All of these requirements should be realized with very Table 4 Basic data for insert and final cutting parameters
limited funding resources. Description Values
RCGX Full Face PCBN grade Insert size 0900700T-
25VM
2.2 Suggested Solution
Insert type
Analysis of literature and taking into account economic
and other limiting factors resulted in the proposal of
application of cold air for cooling of the tool and workpiece.
Installing a cold air nozzle is simple and requires only the CRDCN 3225P 09-A
installation of compressed air hose on the column of the
machine. Accordingly, a SARA vortex tube was purchased. Tool holder

Table 2 Vortex tube data

Description Values Spindle speed n = 13 min−1
Supplier SARA Feed rate s = 0,1 mm/rev
Air pressure at the inlet 3 to 5 bars Depth of cut a = 0,1 mm
Cold air outlet lowest −48 °C Raceway machining length l = 83 mm, number of
Hot air outlet do 100 °C passes i = 7
Pass interval
Air consumption at 7-8 bar 270 l/min Insert machining time for 1 pass t1 = 63.85 min
Price of the device €409 + VAT Total insert machining time for i = 7·t1 = 446.95 min

Table 5 Cooling data

Description Values
Air pressure on input in
6 to 8 bars
a vortex tube

Measuring instrument

Figure 3 Vortex tube

Rothewald Infra-Red digital thermometer with
Table 3 Basic machine data Laser Pointer
Description Values Temperature measuring
Machine Vertical turning machine (See Fig. 3) −50 °C to 750 °C
range
Year of production 1984. Measured temperature −11 °C (see Fig. 5)
Max. workpiece diameter 2500 mm Measuring accuracy about ±2%
Max workpiece height 2000 mm
Total turning height 900 mm
Cooling system Exist

Figure 5 Temperature measurement of cold air on vortex tube outlet in workshop

condition

Application of spot cooling of the tool with cold air

Figure 4 Turning machine during final machining of induction hardened raceway gave
is shown in Figs. 6 and 7.

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 Mladen BOŠNJAKOVIĆ et al.: VORTEX COOLED AIR TURNING OF INDUCTION-HARDENED RACEWAY ON THE WIND TURBINE-BEARING RING

savings. That is important information for the machining

plan because ordering 20 inserts (minimum) costs less
related to orders of only one insert which could cost from
€160 to €215.
• When machined with spot cooling, the quality of surface
finish is improved due to minimized heat input (also,
material accumulation on the insert tip is less).
• Finally, decreasing of raceway roundness after final
machining from 0.2 to 0.1 mm and changes in measure
over balls is less than 0.1 mm, which means that there is
no reason for additional machining of both rings before
mounting.

The increase in operating costs due to cooling air

consumption is not significant. For cost of 0.02 €/m3 of the
compressed air and consumption 0.27 m3/h, the compressed
Figure 6 Final machining of induction hardened race with spot cooling
air cost is €0.4 for an hour of the machine work.

4 CONCLUSION

Air spot cooling during turning of hard materials could

extend tool life of CBN cutting inserts up to 100%, which
could lead to significant savings at tool purchasing. Heat
input in the hardened area had been significantly decreased,
which decreased dimensional change measured 24 hours
after final machining of the raceway. The quality of surface
finish was improved, too.
In accordance with obtained results, the vortex tube air-
cooling systems proved to be effective at dissipating the heat
from the tool tip, proving that air-cooling is an effective
method of cooling tool tip.

5 REFERENCES
Figure 7 Detail of final machining with spot cooling
[1] Dyck, M. (2007). Beitrag zur Analyse thermisch bedingter
3 DISCUSSION Werkstückdeformationen in Trockenbearbeitungsprozessen.
Dr.-Ing. Dissertation wbk Institute of Production Science,
The following results have been obtained: Karlsruhe.
[2] Klocke, F., Kneer, R., Burghold, M., Deppermann, M., Peng,
• First, it was noticed that there is no characteristic color
B., & Puls, H. (2018). Modelling and Compensation of
of the machined chip. Thermoelastic Workpiece Deformation in Dry Cutting. In:
• There is no characteristic point of burnout chips on Thermal effects in complex machining processes. Lecture
cutting edge due to the fact that cold air decreases Notes in Production Engineering. Springer, Cham,
temperature in point of contact for cutting edge and Switzerland, 63-94. https://doi.org/10.1007/978-3-319-57120-1
raceway. [3] Aydin, M., Karakuzu, C., Uçar, M., Cengiz, A., & Çavuşlu, M.
• During machining without cooling only one side of the A. (2013). Prediction of surface roughness and cutting zone
insert was used for machining of one raceway (1 ring), temperature in dry turning processes of AISI304 stainless steel
and after the application of spot cooling, one side of the using ANFIS with PSO learning. International Journal of
Advanced Manufacturing Technology, 67(1-4), 957-967.
insert performed machining on two raceways (2 rings).
https://doi.org/10.1007/s00170-012-4540-2
That was a surprising result because the insert is [4] Weinert, K., Inasaki, I., Sutherland, J. W., & Wakabayashi, T.
expansive (135 €/piece) and it has only two sides (round (2004). Dry machining and minimum quantity lubrication.
insert which could be set in two positions). The CIRP Annals - Manufacturing Technology, 53(2), 511-537.
durability of the insert was increased for 100% during https://doi.org/10.1016/S0007-8506(07)60027-4
machining of induction hardened raceway with one pass [5] Sharma, V. S., Dogra, M., & Suri, N. M. (2009). Cooling
time of about 1 hour. techniques for improved productivity in turning. International
• The number of workpieces was 27 inner and 27 outer Journal of Machine Tools and Manufacture, 49(6), 435-453.
rings. It means that with spot cooling one insert https://doi.org/10.1016/j.ijmachtools.2008.12.010
[6] Nandy, A. K., Gowrishankar, M. C., & Paul, S. (2009). Some
machined 4 rings instead of only two; therefore, to
studies on high-pressure cooling in turning of Ti-6Al-4V.
machine the rings 14 inserts were spent instead of 28 International Journal of Machine Tools and Manufacture,
inserts without cooling. This allows for significant

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49(2), 182-198. https://doi.org/10.1016/j.ijmachtools.2008.08.008

[7] Duspara, M., Kosec, B., Stoić, M., Kramar, D., & Stoić, A.
(2013). Application of vortex tube for tool cooling. Journal of
Production Engineering, 16(2), 41-44.
[8] Lahres, M., Doerfel, O., & Neumüller, R. (1999). Applicability
of different hard coatings in dry machining an austenitic steel.
Surface and Coatings Technology, 120-121, 687-691.
https://doi.org/10.1016/S0257-8972(99)00359-X
[9] Choi, H. Z., Lee, S. W., & Jeong, H. D. (2002). The cooling
effects of compressed cold air in cylindrical grinding with
alumina and CBN wheels. Journal of Materials Processing
Technology, 127(2), 155-158.
https://doi.org/10.1016/S0924-0136(02)00117-6
[10] Abdelghany, S. T. (2018). Three-Dimensional Computational
Investigation of the Power Separation and Flow Anatomy in
the Vortex Tube. Journal of Scientific and Engineering
Research, 5(1), 197-212.
[11] Pinar, A. M., Uluer, O., & Kirmaci, V. (2009). Optimization of
counter flow Ranque-Hilsch vortex tube performance using
Taguchi method. International Journal of Refrigeration, 12(6),
1487-1494. https://doi.org/10.1016/j.ijrefrig.2009.02.018
[12] Liu, J. & Kevin Chou, Y. (2007). On temperatures and tool
wear in machining hypereutectic Al-Si alloys with vortex-tube
cooling. International Journal of Machine Tools and
Manufacture, 47(3-4), 635-645.
https://doi.org/10.1016/j.ijmachtools.2006.04.008
[13] Sutter, G. & Ranc, N. (2007). Temperature fields in a chip
during high-speed orthogonal cutting-An experimental
investigation. International Journal of Machine Tools and
Manufacture, 47(10), 1507–1517.
https://doi.org/10.1016/j.ijmachtools.2006.11.012

Authors’ contacts:

Mladen BOŠNJAKOVIĆ, PhD, Assis. Prof.

Corresponding author
Technical Department, College of Slavonski Brod,
M. Budaka 1, 35000 Slavonski Brod, Croatia,
mladen.bosnjakovic@vusb.hr

Olivera MAGLIĆ, MSc

Technical Department, College of Slavonski Brod,
Dr. M. Budaka 1, 35000 Slavonski Brod, Croatia,
omaglic@vusb.hr

Dragomir MOŠKUN, MSc

Đuro Đaković Strojna obrada d.o.o.
dr. Mile Budaka 1, 35000 Slavonski Brod, Croatia
dmoskun@strojna-obrada.hr

Zoran CRNAC, MSc

Technical school,
E. Kumičića 55, 35000 Slavonski Brod, Croatia
zcrnac2@gmail.com

234 TECHNICAL JOURNAL 13, 3(2019), 230-234

ISSN 1846-6168 (Print), ISSN 1848-5588 (Online) Preliminary communication
https://doi.org/10.31803/tg-20190518181647

THE USE OF CEMENT CONCRETE PAVEMENTS FOR ROADS, DEPENDING ON CLIMATIC

CONDITIONS

Iryna SOLONENKO

Abstract: The development of road network infrastructure is an important component of the economic development of the European Union. Updating of the road network
contributes to the integration of the economies of countries into a coherent whole. The road network provides the free movement of citizens, the movement of goods and the
effective implementation of various services. The increase in the length of the road network leads to an increase in the financial and material costs necessary to ensure its
maintenance and repair. One of the ways to reduce costs is by strengthening the physic-mechanical and operational characteristics of the pavement due to the widespread use
of cement concrete. The quality of the pavement of cement concrete depends largely on the rational selection of its composition. This allows a significant increase in the durability
of road pavement. The purpose of the research was: the development of recommendations for the rational selection of the composition of the road pavement material of cement
concrete, aimed at upgrading longevity, and taking into account its frost resistance grade. According to the goal, the following tasks were developed: the analyses of the climatic
zones in which the road network of the European Union is located; the development of a research plan, a selection of the response function and influence factors; the study of
physico-mechanical and operational characteristics of the researched material of road pavement; on the basis of the obtained data, the calculation of the complex of experimental-
statistical models, which describe the physico-mechanical and operational characteristics of the road pavement material; on the basis of experimental statistical models, a method
was proposed for selecting the rational compositions of the cement concrete pavement road material depending on the conditions of its application. The results presented in the
article can be used in engineering and scientific practice for the selection of road pavement from cement concrete for highways.

Keywords: cement concrete; experimental statistical models; highway; road pavement; transport corridor; weather conditions

1 INTRODUCTION Table 1 The length of main roads, highways and specific sections of roads in the
EU countries [4]
Ground
The network of European roads has a considerable No. Country
Main-line Hard road
road General
length. They ensure the stable development of the European highway pavement
pavement
Union (EU) countries. European roads are combined in a 1 Austria 2 223 200 000 0 202223
number of transport corridors. The main direction of traffic 2 Belgium 1 763 120 514 33 498 155775
in these corridors: from north to south and from west to east. 3 Bulgaria 801 43 649 440 44890
4 Great Britain 3 557 344 000 54 350 401907
They enable the free movement of citizens and various goods 5 Hungary 1 481 76 075 123 492 201048
and the performance of necessary services [1]. EU roads are 6 Germany 12 917 644 480 0 657397
directly adjacent to the road network of Belarus, Ukraine, 7 Greece 2 311 107 406 9 594 119311
Moldova and Russia. The distinctiveness of the roads of 8 Denmark 1 205 74 558 0 75763
Ukraine and Moldova is the low quality of the road 9 Ireland 1 224 91 145 5 457 97826
10 Spain 16 583 683 175 0 699758
pavement, which is caused by the insufficient allocation of
11 Italy 6 758 487 700 0 485458
funds for their maintenance and repair. 12 Cyprus 254 8 564 4 442 13260
As the analysis of the works [2, 3] shows, the condition 13 Latvia 0 14 707 57 737 72444
of the roads mainly depends on the condition of the road 14 Lithuania 0 13 584 8 242 21 826
pavement. The defects of road pavement (Fig. 1) 15 Luxembourg 152 2 899 0 3051
significantly complicate the effective operation of vehicles, 16 Malta 0 2 704 392 3 096
17 Netherlands 2 808 139 295 0 142103
they reduce their speed and endanger traffic safety. 18 Poland 1 566 292 134 131 863 425563
19 Portugal 2 992 71 294 11 606 85892
20 Romania 806 49 873 34 312 84 991
21 Slovakia 432 38 085 5 676 44193
22 Slovenia 618 38 985 0 39603
23 Finland 863 51 016 27 146 79025
24 France 11 882 1 028 446 0 1040328
Rutting Chuck holes, potholes Cracks 25 Croatia 1 318 26 958 0 28276
26 Czech 1 250 130 671 0 131921
27 Sweden 2 050 579 564 0 581614
28 Estonia 115 10 427 47 985 58 527

Cracks transverse Cracks longitudinal Road pavement

An analysis of scientific publications [5, 6, 7] showed
Figure 1 Defects of road pavement that a decrease in the operational costs of maintaining and
repairing roads can be achieved by using cement concrete as
The large length of EU roads (Tab. 1) requires significant a pavement material (Fig. 2).
funds for their maintenance and repair [4].

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 Iryna SOLONENKO: THE USE OF CEMENT CONCRETE PAVEMENTS FOR ROADS, DEPENDING ON CLIMATIC CONDITIONS

- the study of physico-mechanical and operational

characteristics of the researched material of the road
pavement;
- on the basis of the obtained data, the calculation of the
complex of experimental-statistical models, which
describe the physico-mechanical and operational
characteristics of the road pavement material;
- on the basis of experimental statistical models, a method
was proposed for selecting the rational compositions of
the cement concrete pavement road material depending
on the conditions of its application.

Figure 2 Relative construction cost (РΣ), maintenance and repair of roads An analysis of the works [8, 9, 11] showed that the
bitominous with asphalt concrete and cement concrete (a - asphalt concrete, c - durability of the coating for highways made of cement
cement concrete, Pst - construction, Pe - content, Pr - repair, Te – road operation in
time (in years), Pstc = 1,8·Psta)
concrete is significantly affected by the frost resistance of the
material. The resistance of the pavement material to the
As it can be seen from Fig. 3, the total cost of effects of alternating temperatures is important for climatic
construction and maintenance of highways made from zones with unstable negative temperatures (Fig. 2, Tab. 3). In
cement concrete (c), after 10 years of operation, is lower than these zones, throughout the entire winter period, repetitive
for the roads with asphalt concrete (a). Thus, the use of cyclical freeze-thawing of the road pavement is happening.
cement concrete coatings for the European Union countries
reduces the cost of their maintenance and repair.

2 RESULTS AND DISCUSSION

An analysis of literary sources [7, 8, 9] showed that

meeting the requirements on the durability of the cement
concrete pavement for a highway can be achieved by a
rational selection of its composition. The pavement is
significantly affected by loads caused by traffic and climatic
conditions.
The existing normative document EN 206-1 [10] (Tab. 2)
does not take into account the frost resistance of the cement
concrete pavement.

Table 2 Requirements for the material of the cement concrete pavement

for roads (EN 206-1)
Characteristics Demands
Water/cement (W/C) 0.45 ÷ 0.65
Class for compressive strength (MPa) С 35/45 (45) ÷ С 40/50 (50)
Absorption of water, % ≥5 Figure 3 The location of the main roads of the EU countries in climatic zones
Frost resistance -
Abrasion, mm ≥4 As it can be seen from Fig. 2, the roads of the European
Air entrainment, % 4-7 Union lie in different climatic zones. Therefore, different
requirements for frost resistance should be imposed to the
With the purpose of studying the effect of the freeze- pavement material, depending on the climatic zones.
thaw temperature on the compressive strength and abrasion According to the works [7, 8, 9], an improvement in the
of the pavement material of cement concrete, researches have frost resistance of cement concrete can be achieved by
been conducted. introducing an air-entraining additive into its composition, as
The purpose of the research was: the development of well as a microsilica suspension filler. An increased
recommendations for a rational selection of the composition resistance to the abrasion of the material is provided by the
of the road pavement material of cement concrete, aimed at introduction of fibre material in the concrete. This
upgrading longevity, taking into account its frost resistance composition allows the factors that influence the frost
grade. resistance of the pavement material to be determined (Tab.
According to the goal, the following tasks were 4). The range of changes in the number of added components
developed: was determined on the basis of the recommendations of the
- the analyses of the climatic zones in which the road MAPEI firm [12], an analysis of literature [11] and the
network of the European Union is located; personal experience of the author [9].
- the development of a research plan;

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Table 3 Temperature range in winter time depending on the climatic zones - for each point of the experiment plan, the required
No. of The number of freeze-thaw cycles number of samples was formed in the sizes of
Celsius temperature (°C)
zones for 1 year for 10 years
3 −40 … −34 4 40
0.1×0.1×0.1 meters and 0.07×0.07×0.07 meters [13];
4 −34 … −29 5 50 - the obtained samples (Fig. 4a)) were maintained under
5 −29 … −23 5 50 the standard curing of a normal set for 28 days (t = 20
6 −23 … −18 6 60 °C, W = 80%) [13];
7 −18 … −12 8 80 - on the 28th day, samples of 0.07×0.07×0.07 meters were
8 −12 … −7 12 120
9 −7 … −1 20 200
tested for an abrasion test (LKI-3 device) [14];
10 −1 … +4 55 550 - the samples of 0.1×0.1×0.1 meters were tested for
11 more +4 0 0 compressive strength [13];
- the part of the samples of 0.07×0.07×0.07 and
Table 4 Influencing factors and the range of their changes used in research 0.1×0.1×0.1 meters were tested for frost resistance in the
Impact factors freezer (in the freezing room temperature of −50 °C
х1 – air entraining agent additive Mapeplast РТ-1
[15]);
х2 – polypropylene fiber MAPEFIBRE NS 12/ NS 18
х3 – microsilicasuspension filler - after testing for frost resistance (F50, F 100, F150, F
Range of factors change 200), the samples (Fig. 4b)) were tested for the abrasion
Levels of varying factors x1, l/m3 x2, kg/m3 x3, kg/m3 test and compressive strength [13, 14].
Interval 0,142 0,3 7,5
Upper (+1) 0,285 0,6 15 Table 5 The plan of the experiment and the compositions of the studied concretes
Lower (−1) 0 0 0 The plan of experiment The composition of concrete
РТ-1, Fibre, Microsilica suspension,
No х1 х2 х3
l/m3 kg/m3 kg/m3
The main characteristics of the additives and fillers used: 1 −1 −1 −1 0 0 0
- air entraining agent additive Mapeplast РТ-1 2 −1 1 −1 0 0.60 0
("MAPEI"), its inclusion into the concrete mix provides 3 0 0 −1 0.142 0.30 0
an increase in the amount of the entrapped air (designed 4 1 −1 −1 0.285 0 0
to increase the frost resistance of concrete); 5 1 1 −1 0.285 0.60 0
6 −1 0 0 0 0.30 7.50
- microsilica suspension, particle size 0.1-0.2 microns,
7 0 −1 0 0.142 0 7.50
specific surface area – 20.000 m2/kg (designed to 8 0 0 0 0.142 0.30 7.50
increase the strength of concrete and frost resistance, 9 0 1 0 0.142 0.60 7.50
reduces abrasion and the permeability of concrete, etc.); 10 1 0 0 0.285 0.30 7.50
- polypropylene fibre - Mapefibre NS 12/NS 18 11 −1 −1 1 0 0 15
("MAPEI"), diameter – 0.34 mm, fibre length 12-18 mm, 12 −1 1 1 0 0.60 15
13 0 0 1 0.142 0.30 15
density – 9,1×10-4 kg/m3, tensile strength – 700 MPa, 14 1 −1 1 0.285 0 15
(increases the crack resistance of concrete and makes it 15 1 1 1 0.285 0.60 15
resistant to abrasion).

The basic composition of the concrete mix for the

manufacture of prototypes was determined by the method
described in the article [9]:
- portland cement РС – І- Н 500 - 470 kg/m3;
- granite chippings (fractions 5÷20) - 1055 kg/m3;
- sand (fineness modulus = 2.5) - 578 kg/m3;
- superplasticizing admix Dynamon Easy 11 firms of
"MAPEI" firms – 8.55 l/m3; а) b)
Figure 4 The material research: a) material samples prior to freezing and the
- for adding water to the mix, distilled water was used. thawing test; b) material samples after freezing and the thawing test (F 200)

The experiment plan is presented in Tab. 5. The results of the experiments are presented in Tab. 6.
At each point of the experiment plan, at least three The convenience of the analysis for Tab. 6 is shown in a
experiments were conducted with the subsequent graphical form in the Figs. 5 and 6.
determination of the average value of the measurement As it can be seen from the presented data (Fig. 5), the
result. To eliminate the influence of systematic errors caused compositions used for the manufacture of the samples No. 1,
by external conditions, the order of the experiments was 2, 3, 4 can be used as road pavement on the sections of roads
randomized. that are not affected by the freeze-thaw.
The experiments were conducted in the following Under the influence of the freeze-thaw temperature, the
sequence: compressive strength of these samples decreases:
- the necessary amount of additives and fillers were added - for the sample No. 1 at: F50 – 3.1%, F100 – 8.1%, F150
into the basic composition of the concrete mixture (Tab. – 9.5%, F200 – 14.2%;
4); - for the sample No. 2 at: F50 – 4.6%, F100 – 8.4%, F150
–11.8%, F200 – 15.6%;

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 Iryna SOLONENKO: THE USE OF CEMENT CONCRETE PAVEMENTS FOR ROADS, DEPENDING ON CLIMATIC CONDITIONS

- for the sample No. 3 at: F50 – 3.2%, F100 – 6.4%, F150 The compressive strength of the remaining samples
– 9.2%, F200 – 13.2%; subjected to frost resistance tests, even after F200, was more
- for the sample No. 4 it comes down to: F50 – 1.9%, F100 than 50 MPa, which allows its use in all climatic zones.
– 5.4%, F150 – 8%, F200 – 9.3%.

Table 6 The results of the experiments on the compressive strength and abrasion under the cyclic effects of the freeze-thaw test (F)
The results of the experiments
fck.cube (МРа) G (kg/m2)
No fck.cube0 fck.cube50 fck.cube100 fck.cube150 fck.cube200 G0 G50 G100 G150 Gf200
1 2 3 4 5 6 7 8 9 10 11
1 50.25 48.70 46.20 45.50 43.15 0.062 0.065 0.067 0.068 0.071
2 52.60 50.30 48.40 46.70 44.80 0.030 0.033 0.036 0.038 0.039
3 51.80 50.20 48.60 47.20 45.20 0.048 0.050 0.052 0.054 0.057
4 50.10 49.15 47.40 46.10 45.45 0.067 0.069 0.072 0.074 0.076
5 53.40 52.90 52.00 51.10 50.35 0.033 0.036 0.039 0.042 0.045
6 54.60 53.90 52.70 52.00 51.45 0.037 0.040 0.043 0.045 0.048
7 54.20 53.80 52.40 51.20 50.35 0.048 0.053 0.057 0.059 0.061
8 55.20 54.70 53.90 52.00 51.45 0.038 0.040 0.042 0.044 0.047
9 54.70 53.15 52.50 51.70 50.75 0.029 0.032 0.035 0.036 0.039
10 53.75 53.00 52.10 51.40 50.50 0.037 0.039 0.041 0.043 0.046
11 56.50 56.10 55.40 54.90 53.90 0.058 0.060 0.063 0.066 0.069
12 57.80 57.00 56.10 55.20 54.30 0.025 0.028 0.033 0.036 0.039
13 55.45 55.00 54.10 53.25 52.80 0.037 0.039 0.043 0.045 0.048
14 54.90 54.00 53.25 52.30 51.80 0.045 0.048 0.054 0.057 0.062
15 55.00 54.50 54.00 53.85 53.20 0.029 0.031 0.034 0.036 0.038

temperatures have the appearance close to linear. This means

that it is possible to significantly reduce the number of
experiments by limiting them only to the extreme values of
freeze-thaw resistance tests (Fig. 6, f = 0 and f = 200) with
their subsequent linear approximation.

Figure 5 The results of the testing samples for abrasion before and after freezing
and the thawing test (F0, F50, F 100, F150, F 200)

As it can be seen from Fig. 6, the abrasion of road

pavement depends on the number of freeze-thaw cycles. An
analysis of the data shown in (Fig. 6) proved that the samples
of the material in which the loss of mass G was the following
were the best in frost resistance: Figure 6 The results of the testing samples for compressive strength before and
- for the sample No. 2 at: F50 – 0.033 kg/m2, F100 – 0.036 after freezing and the thawing test (F0, F50, F 100, F150, F 200)
kg/m2, F150 – 0.038 kg/m2, F200 – 0.039 kg/m2;
- for the sample No. 5 at: F50 – 0.036 kg/m2, F100 – The data used from Tab. 6 with the help of the Compex
0.039 kg/m2, F150 – 0.042 kg/m2, F200 – 0.045 kg/m2; program [16] were obtained by ES-models in the form of a
- for the sample No. 9 at: F50 – 0.032 kg/m2, F100 – 0.035 polynomial dependence of the form:
kg/m2, F150 – 0.036 kg/m2, F200 – 0.039 kg/m2;
n n n n n n
- for the sample No. 15 at: F50 – 0.031 kg/m2, F100 –
b0 + ∑ bi хi + ∑
y= ∑ bik хi хk + ∑ ∑ ∑ bikl хi хk xl + ...,
0.034 kg/m2, F150 – 0.036 kg/m2, F200 – 0.038 kg/m2. 1
i= 1 k =+
i= i 1 1 k =+
i= i 1 l =+
k 1 (1)
The worst indicators have the following samples: No. 1,
No. 4, No. 7, No. 11 and No. 14. Where: y – the response function, b0, bik, bikl –
As it can be seen from Figs. 5 and 6, the dependence of coefficients of the multiple regression equation, xi –
the change in compressive strength and the loss of mass of normalized value of the influence factor.
the specimens at abrasion under the influence of freeze-thaw For the convenience of calculating mathematical models,
the scale of the factors of influence was chosen so that the

238 TECHNICAL JOURNAL 13, 3(2019), 235-240

 Iryna SOLONENKO: THE USE OF CEMENT CONCRETE PAVEMENTS FOR ROADS, DEPENDING ON CLIMATIC CONDITIONS

value of the upper level was equal to +1, and the lower to –1. I
= xi − xi 0
The origin of the coordinates of the influence factors was (3)
transformed and the transition to the normalized value of
each factor was made: The description of the methods for calculating the
coefficients of regression models is beyond the scope of this
article, but if necessary, you can refer to the works [16, 17].
( хi − xi 0 ) The calculated mathematical models describing the
хi =
I (2) change in the compressive strength (fck.cube0, fck.cube200) and
abrasion (G0, G200) of the pavement material before and after
the freezing thawing resistance test of the test samples (F
Where: xi – normalized value; хi – natural value; хi 0 –
 
200) are presented in Tab. 7.
main level; I – variability interval:

Table 7 Mathematical models describing the change in the compressive strength (fck.cube0, fck.cube200) and abrasion (G0, G200) of the pavement material before and after the freezing
thawing resistance test
No Response function ES-models
1 fck.cube0 (МPа) = 54.49 – 0.46х1 – 0.63х1х3 + 0.75х2 – 0.53х2х3 + 2.15х3 – 0.71x32 (4)
2 G0 (kg/m2) = 0.04 + 0.002x1x2 – 0.002x1x3 – 0.01х2 + 0.002x2x3 – 0.04x3 + 0.004x32 (5)
3 fck.cube200 (МPа) = 51.29 + 0.28х1 – 0.85х1х3 +0.24х2 – 0.31х2х3 +2.69х3 (6)
4 G200 (kg/m2) = 0.05 + 0.001x1x2 – 0.002x1x3 – 0.01х2 + 0.003x22 + 0.001x2x3 – 0.003x3 + 0.006x32 (7)

- according to the Fig. 3 and Tab. 3, the number of freeze-

thaw cycles for one year is determined;
- depending on the cycle life of automotive coating and the
number of freeze-thaw cycles, resistance to alternating
temperatures for the entire life time of the pavement is
determined;
- deferring the values of freeze-thaw cycles along the
ordinate axis (OF), we build the axis perpendicular to the
intersection with the direct defining fck.cube, and similarly
for G.

Figure 7 The example of using the mathematical models No. 1 and 3 for assessing
the resistance of the sample No. 5 to the effect of the freeze-thaw cycles (F) on
compressive strength

The obtained mathematical models allow us to determine

the indicators of compressive strength and the abrasion of the
road pavement material with a different combination of
influence factors lying in predetermined intervals (Tab. 7).
To convert the results of the calculations using
mathematical models into real physical quantities, a reverse
transition from a standardized scale to a natural scale was
made, using Eq. (2). The illustration of the use of
mathematical models (for the sample No. 5) is presented in Figure 8 The example of using the mathematical models No. 2 and 4 for assessing
the Figs. 7 and 8. the resistance of the sample No. 5 to the effect of freeze-thaw cycles (F) on
abrasion
The calculations of the compressive strength and
abrasion with consideration of the freeze-thaw resistance for
3 CONCLUSIONS
cement concrete pavements are made in the following
sequence:
The researches have allowed the proposition of a method
- the substituting formulas 4 ÷ 7 (Figs. 7 and 8) and the
for determining the magnitude of changes in the compressive
data of the influence factors (Tabs. 4 and 5) will
strength and weight loss of samples when the road pavement
determine the values - compressive strength (fck.cube) and
material is abraded under the influence of freeze-thaw
abrasion (G), when exposed to the freeze-thaw
temperatures.
temperature (at F = 0 and F = 200 cycles);
An analysis of climatic zones in which the EU road
- through the obtained values, linear interpolation is
network is located was carried out in order to determine the
performed and if necessary, extrapolation of the results
necessary freeze-thaw resistance of the road pavement
is performed (Figs. 7 and 8);
material for each of them.

TEHNIČKI GLASNIK 13, 3(2019), 235-240 239

 Iryna SOLONENKO: THE USE OF CEMENT CONCRETE PAVEMENTS FOR ROADS, DEPENDING ON CLIMATIC CONDITIONS

The study of changes in the properties of the pavement mode: https://www.researchgate.net/publication/276334935_

material depending on the number of freeze-thaw cycles has abrasion_resistance_and_transport_properties_of_road_concr
been carried out. ete
[12] MAPEI. Agent additive for concrete and cement mortars.
The recommendations for a rational selection of the
Access mode: http://ukrpolystroy.com.ua/shop/dobavka-
composition of the pavement material of the cement concrete mapei/
depending on the requirements for the freeze-thaw resistance [13] DSTU B V.2.7-214:2009. Building materials. Concrete
were developed. Methods of determining the strength of control samples. Kyiv,
On the basis of the experimental statistical models 2009, 35 p.
obtained, a method is proposed for selecting the rational [14] DSTU B V.2.7-212:2009. Building materials. Concrete
compositions of cement concrete road pavement materials, Methods of definition of erosion. Kiev, 2009, 8 p.
depending on the required freeze-thaw resistance. [15] DSTU B V.2.7-49-96:1997. Building materials. Concrete. The
When conducting research, additives and fillers from the accelerated methods for determining frost resistance during
multiple freezing and thawing. Kyiv, 1997, 10 p.
MAPEI firm were used, which were kindly provided to the
[16] Voznesensky, V. A. (1981). The statistical Methods for
author by a representative of the company. If necessary, Experimental Planning in Techno-Economic Research / V. A.
similar results can be obtained for the components from other Voznesensky. 2nd ed. M.: Finance and Statistics, 263 p.
manufacturer firms. [17] Voznesensky, V. A. (1989). The numerical methods for solving
construction and technological problems on a computer / V. A.
4 REFERENCES Voznesensky, T. V. Lyashenko, B. L. Ogarkov. Kyiv: Vishcha
School, 327 p.
[1] The European transport corridors [Electronic resource]. –
Access mode: http://dergachev.ru/geop_events/210515-
02.html#.XHZyGNDSjmZ (Available: 07 March 2019) Author’s contact:
[2] The classification and description of typical road maintenance
defects [Electronic resource]. – Access Iryna SOLONENKO, PhD, Head teacher
mode:http://www.steps.ru/article/klassifikatsiya_i_opisanie_ti Odessa State Academy of Civil Engineering and Architecture,
4, Didrikhsona St., 65029 Odessa, Ukraine
pichnyh_defektov_soderzhaniya_avtomobilnyh_dorog
Tel./Fax: +380974666579,
(Available: 09 March 2019) E-mail: odarina08@rambler.ru
[3] Shaikh Sameer J., Kanahya Bhutada, Sainath Poharkar,
Devidas Chavade, & Kedarnath. (2018). Road Defects and
Highway Maintenance. IOSR Journal of Mechanical and Civil
Engineering (IOSR-JMCE), 15(2), Ver. II (Mar. - Apr.), 43-47.
www.iosrjournals.org
[4] The length of highways in Europe [Electronic resource]. –
Access mode: https://autotraveler.ru/spravka/road-length-in-
europe.html#.XJFbDDpS__8. (Available: 05 March 2019).
[5] Solonenko, I. P. & Bratcheko, P. G. (2016). The harmonization
of the regulatory framework of Ukraine with international
requirements for road coverage. The Sixth International
Scientific and Practical Conference. Metrology, technical
regulation, quality: achievements and prospects - OGATRK,
Odesa, 63-65.
[6] Vyrozhemskyi, V., Krayushkina, K., & Bidnenko, N. (2017).
Durable high strength cement concrete topping for asphalt
roads. IOP Conference Series: Materials Science and
Engineering, 236, 012031.
https://doi.org/10.1088/1757-899X/236/1/012031
[7] Pogorelov, S. N. & Semenyak G. S. (2016). Frost Resistance
of the Steel Fiber Reinforced Concrete Containing Active
Mineral Additives. Procedia Engineering, 150, 1491-1495.
https://doi.org/10.1016/j.proeng.2016.07.088
[8] Delatte, N. J. (2014). Concrete Pavement Design, Construction
and Performance, 2nd Ed., CRC Press, London.
https://doi.org/10.1201/b17043
[9] Solonenko, I. P. (2015). The structure and properties of
modified cement concrete coatings for highways, Dissertation.
Sciences: spec. 05.23.05 Construction materials and products
/ I. P. Solonenko. OGASA. Odessa, 155 p.
[10] Concrete - Part 1: general of technological requirements,
production and quality control. (EN 206-1) Per. from English
Yu. S. Volkov. - Brussels, 2000. - 68 p.
[11] Mardani-Aghabaglou, A., Hosseinnezhad, H., Boyacı, O. C.,
Arıöz, Ö., Yaman, İ. Ö., & Ramyar, K. (2014). Abrasion
resistance and transport properties of road concrete. Access

240 TECHNICAL JOURNAL 13, 3(2019), 235-240

ISSN 1846-6168 (Print), ISSN 1848-5588 (Online) Subject review
https://doi.org/10.31803/tg-20190328111708

FINITE DIFFERENCE SOLUTION OF PLATE BENDING USING WOLFRAM MATHEMATICA

Katarina PISAČIĆ, Marko HORVAT, Zlatko BOTAK

Abstract: This article describes the procedure of calculating deflection of rectangular plate using a finite difference method, programmed in Wolfram Mathematica. Homogenous
rectangular plate under uniform pressure is simulated for this paper. In the introduction, basic assumptions are given and the problem is defined. Chapters that follow describe
basic definitions for plate bending, deflection, slope and curvature. The following boundary condition is used in this article: rectangular plate is wedged on one side and simply
supported on three sides. Using finite difference method, linear equation system is given and solved in Wolfram Mathematica. System of equations is built using the mapping
function and solved with solve function. Solutions are given in the graphs. Such obtained solutions are compared to the finite element method solver NastranInCad.

Keywords: Finite difference method; NastranInCad; Mathematica

1 INTRODUCTION (elastic plane). The change of deflection shown in Fig. 1

equals:
The article shows the implementation of the finite
difference method in solving the plate bending problem. Due ∂w ∂w
to the large number of equations, the system is solved using ∂w= ∂x + ∂y (1)
∂x ∂y
a computer. For these needs, appropriate symbolic
programming software (Wolfram Mathematica, MATLAB,
Mathcad, Sage, etc.) is selected and appropriate functions are Slope in this case is:
used. In this paper, Wolfram Mathematica is used.
Bending of rectangular plates depends mostly on the ∂w ∂w ∂x ∂w ∂y ∂w ∂w
= + = cos α + sin α (2)
ratio of plate thickness compared to other dimensions. ∂n ∂x ∂n ∂y ∂n ∂x ∂y
Usually we differ the following:
1) small deflection thin plates,
2) large deflection thin plates,
3) thick plates.

If deflection of a thin plate comparing to plate thickness

is relatively small, bending theory can be provided according
to the following assumptions [1]:
1) There are no deformations in the middle cross section of
the plate. This cross section is neutral during bending.
2) Points lined in neutral plane of a plate before deforming
stay on a normal plane after bending.
3) Normal stress in transversal direction can be omitted.

With those assumptions plate deflection can be given as

a function of two coordinates in the plate plane. This function
complies with partial linear differential equations that
together with boundary conditions define plate deflections. If
some conditions cannot be satisfied, then additional
conditions should be defined or some additions to formula Figure 1 Slope of a middle plane [1]
should be given to define problem in a satisfactory way.
When determining curvature of plate with small
2 DEFLECTION AND CURVATURE OF A RECTANGULAR deflections, the slope in any direction is equal to the
PLATE corresponding angle which tangent on a surface makes with
axes x and y [1]. It follows:
The middle plane of a plate we define as xy plane. While
the plate is bending, particles of xy plane are moved for a 1 ∂  ∂w  ∂2 w
small displacement w and shape the middle plane of a plate =
−  =− 2 (3)
rx ∂x  ∂x  ∂x

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 Katarina PISAČIĆ et al.: FINITE DIFFERENCE SOLUTION OF PLATE BENDING USING WOLFRAM MATHEMATICA

1 ∂  ∂w  ∂2 w Ez  1 1
=
−  = − 2 (4) =σy  +ν 
2 
(12)
ry ∂y  ∂y  ∂y 1 −ν  ry rx 

For any direction:

1 ∂  ∂w  ∂2 w
=−  = − 2 (5)
rn ∂n  ∂n  ∂n
1 1 1 1
= cos 2 α − sin 2α + sin 2 α (6)
rn rx rxy ry

where:

1 ∂2 w 1 ∂2 w Figure 3 Pure bending [1]

= − 2 , = − 2 (7)
rx ∂x ry ∂y
1 ∂2 w
= (8)
rxy ∂x∂y

Figure 4 Differential element with elementary layer

Figure 2 Curvature of a middle plane
Normal stresses can be replaced with moments:
3 RELATION BETWEEN BENDING MOMENTS AND
CURVATURE h /2

∫ σ x z dydz = M x dy (13)
When bending the beam, the assumption is that the beam − h /2
section is unformed and rotates around the neutral axis so that h /2
its position is normal in relation to the elastic line. Axis z is ∫ σ y z dxdz = M y dx (14)
perpendicular to the middle plane and directed downwards − h /2
(Fig. 3).
Elongations of elementary layer abcd are shown in Fig. Substituting (9) and (10):
4:
1 1
z M x D  +ν 
= (15)
εx = , (9)  rx ry 
rx 
1 1
z M y D  +ν 
= (16)
εy = . (10)  ry rx 
ry 

Matching strains are: Where D is flexural rigidity:

Ez  1 1 Eh3
=σx  +ν  (11) D= (17)
2 
1 −ν  rx ry  12(1 −ν 2 )

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 Katarina PISAČIĆ et al.: FINITE DIFFERENCE SOLUTION OF PLATE BENDING USING WOLFRAM MATHEMATICA

4 DIFFERENTIAL EQUATIONS OF PLATE BENDING and

∂2 w
We assume that the load on the surface is perpendicular M xy = D(1 ν )
− M yx =− (25)
to the surface and that the deflections are small compared to ∂x∂y
the thickness of the surface. At the borders we assume that
the boundaries of the plates are free and these reactions are Deflection equation is [1, 2, 3, 4]
perpendicular to the plate, and the deformation of the central
surface is neglected. ∂4 w ∂4 w ∂4 w q
4
+2 2 2
+ 4
= (26)
∂x ∂x ∂y ∂y D

Figure 5 Bending of a differential element [1]

Shear forces shown in Fig. 5 are:

h/2
Qx = ∫ τ xz dz (18)
−h/ 2
h /2 Figure 6 Middle plane of differential element [1]
Qy = ∫ τ yz dz (19)
5 BOUNDARY CONDITIONS
− h /2

Taking into consideration all moments and forces the Assuming the plate is rectangular and the edges are
following equilibrium equation is: parallel to coordinate axes, we set boundary conditions for
the plate.
∂M yx ∂M x
dxdy + dydx − Qx dxdy =
0 (20) 5.1 Wedged Edge
∂y ∂x
If the edge is wedged, deflection on the edge equals zero
Simplified: and tangential plane is corresponding to middle plane of
unloaded plate. For edge x = a
∂M yx ∂M x
+ 0
− Qx = (21) ( w) x = a = 0 , (27)
∂y ∂x
 ∂w 
  =0 (28)
Equation of differential element is:  ∂x  x = a

∂2 M x ∂2 M y ∂ 2 M xy 5.2 Freely Supported Edge

+ +2 −q
= (22)
∂x 2 ∂y 2 ∂x∂y
If the edge x = a is freely supported, deflection on the
boundary must be zero and bending moment must be zero;
Moments are equal to: the conditions are the following:

 ∂2 w ∂2w  ( w) x = a = 0 (29)
− D  2 + ν 2 
Mx = (23)
∂ w2 2
 ∂x ∂y  ∂ w
 2 + ν 2  0
= (30)
 ∂x ∂y  x = a
∂ w 2 2
∂ w
− D  2 + ν 2 
My = (24)
 ∂y ∂x 

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 Katarina PISAČIĆ et al.: FINITE DIFFERENCE SOLUTION OF PLATE BENDING USING WOLFRAM MATHEMATICA

6 FINITE DIFFERENCE METHOD  dφ  φi +1 − φi φi +1 − φi

=
  = (33)
 dx i xi +1 − xi ∆x
Finite difference method is a numerical method for
solving differential equations. While solving problem of
plate bending, derivations of functions of deflection, moment
and shear force are approximated by finite differences of
deflection in neighboring points. These points are called
nodes and they represent finite difference mesh [4, 5]. When
solving plate bending, we use two-dimensional mesh, shown
in Fig. 7.
The definition of derivation is a starting point for finite
difference method:

 dφ  φ ( xi + ∆x) − φ ( xi )
  = ∆lim (31)
d
  x x → 0 ∆x

Figure 8 Finite difference schemes

Backward difference is calculated by:

 dφ  φi − φi −1 φi − φi −1
=
  = (34)
 dx i xi − xi −1 ∆x

Central difference:

 dφ  φi +1 − φi −1 φi +1 − φi −1
=
  = (35)
 dx i xi +1 − xi −1 2∆x

Using central difference derivatives have following

forms:

∂w wi +1, j − wi −1, j
= (36)
∂x 2∆x
Figure 7 Finite difference mesh ∂w wi , j +1 − wi , j −1
= (37)
Fig. 8 shows derivation as a tangent of a function ϕ(x). ∂y 2∆y
We can approximate the tangent of a function with the line ∂2 w wi +1, j − 2 wi , j + wi −1, j
which represents forward difference, backward difference or 2
= (38)
∂x ∆x 2
central difference [5]
Forward difference is given by: ∂2 w wi , j +1 − 2 wi , j + wi , j −1
= (39)
 dφ  φi +1 − φi φi +1 − φi ∂y 2 ∆y 2
=  = (32)
 dx i xi +1 − xi ∆x ∂4 w wi + 2, j − 4 wi +1, j + 6 wi , j − 4 wi −1, j + wi − 2, j
4
= (40)
∂x ∆x 4
Forward difference is calculated by:
∂4 w wi , j + 2 − 4 wi , j +1 + 6 wi , j − 4 wi , j −1 + wi , j − 2
= (41)
∂y 4 ∆y 4

∂4 w wi +1, j +1 − 2 wi +1, j + wi +1, j −1 − 2 wi , j +1 + 4 wi , j − 2 wi , j −1 + wi −1, j +1 − 2 wi −1, j + wi −1, j −1

2 2
= (42)
∂x ∂y ∆x 2 ∆y 2

7 PLATE BENDING SOLUTION is wedged, as shown in Fig. 9. The rectangular plate is 5 mm

thick and the size of the final element is 50 mm. The plate is
In this paper, the problem of bending a rectangular plate loaded with a pressure of 20 MPa.
with a continuous load across the surface will be solved. Plate
has edges freely supported on three sides, and the fourth edge

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4. We make an array of values for the solution. Each entry

in the array corresponds to the value of the unknown
function at a point in space.
W=Array[w,{xdivisions+5,ydivisions+5},{{xmino,xmax
o},{ymino,ymaxo}}];
WW=Array[w,{xdivisions+1,ydivisions+1},{{xmin,xma
x},{ymin,ymax}}];

5. We set find finite difference approximations for different

derivatives of w.
dwdx=Table[(W[[i+1,j]]-W[[i-
Figure 9 Rectangular plate boundary conditions 1,j]])/(2*dx),{i,3,Length[xgrid]-2},{j,3,Length[ygrid]-2}];
dwdy=Table[(W[[i,j+1]]-W[[i,j-
7.1 Wolfram Mathematica Code 1]])/(2*dy),{i,3,Length[xgrid]-2},{j,3,Length[ygrid]-2}];
dwdx2=Table[(W[[i+1,j]]-2W[[i,j]]+W[[i-
The Wolfram Mathematica program was used to solve 1,j]])/(dx^2),{i,3,Length[xgrid]-2},{j,3,Length[ygrid]-2}];
the system of algebraic equations. The matrix of the finite dwdy2=Table[(W[[i,j+1]]-2W[[i,j]]+W[[i,j-
difference elements was created and by mapping function 1]])/(dy^2),{i,3,Length[xgrid]-2},{j,3,Length[ygrid]-2}];
each element was mapped to corresponding expression of
dwdx4=Table[(W[[i+2,j]]-4W[[i+1,j]]+6W[[i,j]]-4W[[i-
finite differences [7, 8]. Additional equations are set for edge
1,j]]+W[[i-2,j]])/(dx^4),{i,3,Length[xgrid]-
elements, according to boundary conditions.
The code is given in segments: 2},{j,3,Length[ygrid]-2}];
1. We define constants.
ν=0.3;
dwdy4=Table[(W[[i,j+2]]-4W[[i,j+1]]+6W[[i,j]]-4W[[i,j-
ee=210*10^9;
1]]+W[[i,j-2]])/(dy^4),{i,3,Length[xgrid]-
p=-20000;
2},{j,3,Length[ygrid]-2}];
h=5;
dwdx2dy2=Table[(W[[i+1,j+1]]-2W[[i+1,j]]+W[[i+1,j-1]]-
DD=(ee h3)/(12 (1-ν2));
2W[[i,j+1]]+4W[[i,j]]-2W[[i,j-1]]+W[[i-1,j+1]]-2W[[i-
a=1000;
1,j]]+W[[i-1,j-1]])/(dx^2*dy^2),{i,3,Length[xgrid]-
b=1a;¸
2},{j,3,Length[ygrid]-2}];
q0=p;

2. We define number of elements and boundary elements. 6. We specify boundary conditions.

xmin=-(1/2)a; (*Consider the left-side bc *)
xmax=1/2 a; leftbc=Table[dwdx[[1,k+1]],{k,1,Length[ygrid]-6}];
ymin=-(1/2)b; leftbcw=Table[W[[3,k+1]],{k,3,Length[ygrid]-3}];
ymax=1/2 b; (*Do the same for the right-side bc*)
xdivisions=20; rightbc=Table[dwdx2[[-1,k+1]],{k,1,Length[ygrid]-6}];
ydivisions=20; rightbcw=Table[W[[-3,k+1]],{k,2,Length[ygrid]-4}];
dx=(xmax-xmin)/xdivisions (*And for the bottom side boundary condition*)
dy=(ymax-ymin)/ydivisions bottombc=Table[dwdy2[[k+1,1]],{k,1,Length[xgrid]-6}];
bottombcw=Table[W[[k+1,3]],{k,2,Length[xgrid]-4}];
(*And for the top side bc*)
3. We define grid. topbc=Table[dwdy2[[k+1,-1]],{k,1,Length[xgrid]-6}];
topbcw=Table[W[[k+1,-3]],{k,3,Length[xgrid]-3}];
xmino=xmin-2dx;
ymino=ymin-2dy;
xmaxo=xmax+2dx;
ymaxo=ymax+2dy;
xgrid=Range[xmino,xmaxo,dx];
ygrid=Range[ymino,ymaxo,dy];
grid=Outer[{#1,#2}&,xgrid,ygrid];

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7. We solve boundary equations. 10. We make table of coordinates in three dimensional space
(*takes the left boundary conditions, and solves them and plot solution.
to yield the values of w along the left side *) dataPoints=Table[{xmin+i*dx,ymin+j*dy,solutionArr
wleftw=NSolve[Map[#==0&,leftbcw],Table[W[[3, ay[[i+1,j+1]]},{i,0,Length[xgrid]-5},{j,0,Length[ygrid]-
k]],{k,4,Length[ygrid]-2}]]; 5}];
wleft=NSolve[Map[#==0&,leftbc],Table[W[[2,k]], Min[solutionArray]
{k,4,Length[ygrid]-3}]]; ListPlot3D[Flatten[dataPoints,1],AxesLabel->
(*takes the right boundary conditions, and solves {Style[x,Medium,Blue],
them to yield the values of w along the right side *) Style[y,Medium,Blue],Style[u,Medium,Blue]},
wrightw=NSolve[Map[#==0&,rightbcw],Table[W[ PlotRange->All,ColorFunction-
[-3,k]],{k,3,Length[ygrid]-3}]]; >Function[{x,y,z},Hue[z]]]
wrightt=NSolve[Map[#==0&,rightbc],Table[W[[-
2,k]],{k,4,Length[ygrid]-3}]];
7 SOLUTION
wright=Flatten [wrightt/.wrightw,1];
(*takes the bottom boundary conditions, and solves Using Wolfram Mathamatica program, the program code
them to yield the values of w along the bottom side *) from the previous chapters, we obtained maximum deflection
wbottomw=NSolve[Map[#==0&,bottombcw],Tab of 23.874 mm. A three dimensional graph of this solution is
le[W[[k,3]],{k,3,Length[xgrid]-3}]]; given in Fig. 10.
wbottomm=NSolve[Map[#==0&,bottombc],Tabl
e[W[[k,2]],{k,4,Length[xgrid]-3}]];
wbottom=Flatten [wbottomm/.wbottomw,1];
(*takes the top boundary conditions, and solves them
to yield the values of w along the top side *)
wtopw=NSolve[Map[#==0&,topbcw],Table[W[[k,
-3]],{k,4,Length[xgrid]-2}]];
wtopp=NSolve[Map[#==0&,topbc],Table[W[[k,-
2]],{k,4,Length[xgrid]-3}]];
wtop=Flatten [wtopp/.wtopw,1];
(*This is a list of all the boundary values of w*)
boundary1=Flatten[Join[wleft,wright,wtop,wbott
om]];
boundary2=Flatten[Join[wleftw,wrightw,wtopw,wb
ottomw]];

8. We now create a set of equations. We make a table, with Figure 10 Finite difference solution
each entry corresponding to an interior grid point. Each
entry in the table becomes an equation, from the In order to prove that this solution is correct, the
discretized partial differential equation. We use our NastranInCad finite element analysis program was used.
knowledge of the boundary conditions to eliminate the NastranInCad is used as a part of Autodesk Inventor. In the
values of w on the boundary [7, 8]. Inventor, the finite element method has the maximum error
of 23.67 mm. This solution is shown in Fig. 11.
equations=Map[(q0/DD==#)&,Flatten[Table[dwdx4[[i,
j]]+2*dwdx2dy2[[i,j]]+dwdy4[[i,j]],{i,2,xdivisions},{j,2,y
divisions}],1]/.boundary1/.boundary2];

9. We solve equations and substitute interior values of w

into the equations.
intSol=NSolve[equations,Flatten[W[[4;;Length[xgrid]
-3,4;;Length[ygrid]-3]]]][[1]];
boundarySol=boundary1/.intSol;
solution1=W/.intSol;
solutionArray1=solution1/.intSol/.boundary2;
solutionArray=solutionArray1[[3;;Length[xgrid]-
2,3;;Length[ygrid]-2]];
Figure 11 Finite element solution

246 TECHNICAL JOURNAL 13, 3(2019), 241-247

 Katarina PISAČIĆ et al.: FINITE DIFFERENCE SOLUTION OF PLATE BENDING USING WOLFRAM MATHEMATICA

8 CONCLUSION Authors’ contacts:

Katarina PISAČIĆ, dipl. ing. mech., Senior Lecturer

To solve plate bending problem Wolfram Mathematica’s (Corresponding author)
mapping function was used to create a matrix of equations so University North, University center Varaždin
that each element was provided with correct finite difference 104. brigade 3, 42000 Varaždin, Croatia
katarina.pisacic@unin.hr
equation. Mathematica solver function NSolve was used for
solving the system of equations. Marko HORVAT, dipl. ing. mech., Lecturer
It is also possible to program a custom method that is University North, University center Varaždin
most appropriate for diagonal dominant matrices as used in 104. brigade 3, 42000 Varaždin, Croatia
marko.horvat@unin.hr
[9]. Observing the terms, equations and elements, it is
apparent that we deal with sparse matrices, and the built-in Zlatko BOTAK, PhD, dipl. ing. mech., Senior Lecturer
solver takes quite some time to compute the solution. Time University North, University center Varaždin
is shortened by decreasing the number of elements, but then 104. brigade 3, 42000 Varaždin, Croatia
zlatko.botak@unin.hr
the solution has the larger error.
For this problem, when the element size is 50 mm, the
deviation from finite element method is very small, the
Mathematica solution is 23.87 mm, and Inventor solution is
23.67 mm for the maximum deflection. Unlike the manual
calculation and the use of symbolic programming software,
the use of finite element method (FEM) solver accelerates the
computation process.

5 REFERENCES

[1] Timoshenko, S. & Woinowsky-Krieger, S. (1987). Theory of

plates and shells, McGraw-Hill International Editions,
Engineering Societies Monograph.
[2] Alfirević, I. (2011). Linearna analiza konstrukcija, Sveučilište
u Zagrebu, Fakultet strojarstva i brodogradnje, Zagreb
[3] Grubišić, R. (1997). Teorija konstrukcija I-dio, Primjeri
statičke analize elemenata konstrukcije, Sveučilište u Zagrebu,
Fakultet strojarstva i brodogradnje, Zagreb.
[4] Radenković, D.( 1953). Bending of A Rectangular Plate
Weakend By A Hole, Beograd, Publication de l'Institut
Mathématique, V(05),
[5] Sorić, J. (2009). Uvod u numeričke metode u strojarstvu,
Fakultet strojarstva i brodogradnje, Zagreb 2009.
[6] Roknuzzaman, Md. Hossain, B., Haque, R., & Ahmed, T. U.
(2015) Analysis of Rectangular Plate with Opening by Finite
Difference Method, American Journal of Civil Engineering
and Architecture, 3(5), 165-173.
[7] Nolting, B. Numerically solving PDEs in Mathematica using
finite difference methods, http://datavoreconsulting.com/
programming-tips/numerically-solving-pdes-mathematica-
finite-differences/, available March 2019.
[8] Nolting, B. Finite Difference Method (now with free code!),
http://datavoreconsulting.com/programming-tips/finite-
difference-method-now-free-code/, available March 2019.
[9] Sertic, J., Kozak, D., & Scitovski, R. (2008) LU-decomposition
for solving sparse band matrix systems and its application in
thin plate bending. Transactions of FAMENA, 32(2), 41-48.

TEHNIČKI GLASNIK 13, 3(2019), 241-247 247

ISSN 1846-6168 (Print), ISSN 1848-5588 (Online) Subject review
https://doi.org/10.31803/tg-20190215200430

INTERNET OF THINGS AND SMART WAREHOUSES AS THE FUTURE OF LOGISTICS

Krešimir BUNTAK, Matija KOVAČIĆ, Maja MUTAVDŽIJA

Abstract: Innovations and market changes in warehouse and logistics systems force the adaptation and transformation of the existing business model into a business model
based on modern technology. With the development of the Internet, RFID (radio-frequency identification) technology and sensors, new innovations are being created that allow
the improvement of the existing mode of activity. Implementation of the new technology brings along a number of challenges that organizations must find an adequate response
to. However, warehouse systems are not the only affected by the new technologies. The development of technology and technological innovations enable organizations to develop
sustainability. Sustainable development is imperative due to increasing awareness of the need for environmental protection. The supply chain can also be managed much more
efficiently if sensors that collect information of customer habits and process performance are implemented. Given the accelerating development of Industry 4.0 and the opportunities
offered by newly developed technology, this paper provides an overview of current developments in the implementation of Industry 4.0 technological innovations in logistics.

Keywords: Internet of things; radio-frequency identification; smart technologies; supply chain; warehouses

1 INTRODUCTION systems. Permanent improvements are a particularly

important factor for the logistics industry, which faces
Along with the development of new technologies, new ecological challenges faced with competitiveness-related
ways of managing warehouse systems and logistics costs.
operations are being developed. Internet technologies have The supply chain consists of warehouses, transport
made it possible to connect physical elements to the network, organizations, manufacturers, etc. The importance of
which is the basis for development of the IoT (Internet of creating a sustainable development of the supply chain is
Things). increasing because warehouses, production systems,
The IoT is a network that interconnects physical transport organizations and other stakeholders in the supply
elements capable of collecting performance information that chain are large energy consumers, which means the release
evolves the process or its components such as machines and of large quantities of greenhouse gases. Optimization of the
devices as well as enabling their management. [1] supply chain with the help of technological innovations of
Accordingly, this paper is based on the secondary industry 4.0 enables reducing the amount of greenhouse
research with the aim to present current trends in the gases emitted as well as increasing energy efficiency.
development of technological innovations of industry 4.0 in Furthermore, warehouses become automated under the
logistics, which can determine the sustainable development pressure of the decline in human work efficiency, employee
of the organizational logistics system.
fluctuation dependency, natural migration, and the
With the development of awareness of sustainable
requirement to reduce the cost of logistical processes.
development, green logistics and the reduction of the impact
of logistic and other operations on the environment, the Costs of logistic processes directly correlate with the
applicability of IoT technology is increasing. IoT also allows profitability and economic viability of the logistics system.
control of individual components within logistic processes By reducing them and implementing new technology that
and systems and provides ongoing improvements based on will enable efficiency and productivity increase, logistic
the data collected by sensors placed inside and outside the systems become economically viable. The economic
installed warehouse infrastructure and superstructures. viability of the system is the basis for achieving ecological
The growth of the industry is the consequence of an and social sustainability, which will, as a result, have a
increase in the emissions of harmful gases, especially carbon positive impact on the overall economy.
dioxide [2], which is an increasing problem for the Existing systems used to monitor and manage
environment. performance, which as a result provide data that can be used
Development of technology enables the reduction of the to improve the system, should therefore be enhanced by
negative impact of economic growth. Newly developed technologies such as IoT. The effects of such technologies
technologies are often used in the environmental protection are long-term, and the return on invested resources is
and securing the foundation for sustainable development. inevitable at later stages of business after their
The issue of environmental pollution is not the only implementation.
problem that today’s business organizations are facing. The
demands of interested parties and the environment that is 2 REVIEW OF INDUSTRY 4.0 LITERATURE
often susceptible to turbulence, places on the organization the
imperative of developing new approaches that will meet the IoT technology emerges in the 90th century of the last
increasing demands in organizational environments. century. As the concept, it officially got its name in 1999 [3]
Responding to the increasing demands for quality has
but was officially introduced only in 2008. In 2010, the
influenced the development of continuous improvement

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 Krešimir BUNTAK et al.: INTERNET OF THINGS AND SMART WAREHOUSES AS THE FUTURE OF LOGISTICS

Chinese economy recognized the importance of this of Industry 4.0 on the logistics system. But there are few that
technology and started investing in its development. [4] provide an overview of all technologies affecting the logistics
Automation of production began in the 1950s, when system. In accordance with this, this chapter provides an
robots were used for the first time in manufacturing for overview of all technologies affecting the logistics system.
simple operations [5]. From 2000 to 2015, the use of
industrial robots increased by 150% [6], whereby the trend of 3.1 Warehouse Systems and Industry 4.0
growth is evident. Automation of the manufacturing process
has often been applied in the automotive industry where in The warehouse system itself contains a large number of
the past 9 of 10 robots were sold to one of the car operations aimed at meeting the requirements of the
manufacturers. Furthermore, the importance of robotics and interested parties. Lee, C.K.M., et al (2017) state that the
automation also comes from the fact that the number of development of industry 4.0 has affected a different way in
robots that are implemented in the todays automotive which past activities within the warehouse are taking place.
industry is 50% of the total number of manufactured robots The fourth industrial revolution at the same time marked the
[7] which can imply a gradual return to human labor, or an use of the IoT technology in warehouses which reflected in
increase in the number of industrial sectors that apply robots the efficiency and performance of the storage systems.
in their business. Traditional WMS (warehouse management system) is
Parallel to the development and implementation of enhanced by the IoT, which exploits the full potential of
robots in industrial production warehouses are implementing RFID technology. With the IoT all activities as well as goods
automated systems that allow faster and easier transportation within the warehouse are controlled, which enables their
of goods [7]. manageability. However, the use of the IoT also entails the
Traditionally, in warehouse, all products have been security issues of such systems as they may often become the
labeled with RFID technology developed during the 70s of target of online attacks. [12] Industry 4.0 does not only
the last century, enabling a revolutionary approach to involve the use of the IoT, but also of other technologies that,
improving warehouse operations and reducing storage costs. through communication as one of the feedback components,
The development of RFID technology is based on IFF have an impact on the improvement of logistic processes.
(Identification friend or foe) technology used during World The IoT does not only affect warehouses and warehouse
War II. [8] Although the purpose of RFID was initially to be operations, but also the entire supply chain. Sensors as an
built into the automotive industry, the banking industry, integral part of this technology collect a large amount of data
security and healthcare, [9] later adaptation and refinement that affects the challenges associated with their storage and
proved to be an ideal storage system. Robotization, management. Machado and Shah emphasize that precisely
automation and internet development transform traditional because of this fact the existing warehouses have to be
warehouses into warehouses that, through the IoT and reorganized. In addition, by deploying intelligent systems to
modern computer support, improve their performance and, the warehouse, the logistic superstructure, which has so far
above all, productivity, efficiency and effectiveness. been managed by employees, becomes autonomous,
Growth of globalization and the strengthening of allowing it to move through the warehouse without or with a
capitalism increases the need for industrial development. slight employee intervention. Furthermore, IoT provides
Industry development results in increasing emissions of immediate insight into inventory stock status. Particular
harmful gases. The first attempts to raise awareness of the importance is the ability to manage the entire supply chain as
issues and challenges related to ecological problems were well as communication between its stakeholders. Real-time
first shown in 1962. In 1987, in the report published by information enables logistical operators to gain insight into
WCED, the concept of sustainable development is mentioned logistics operations, in particular the conditions under which
for the first time in the history. Five years later, in 1992, the freight transport is carried out by means of transport, which
basic environmental goals were defined. In 2015, the UN increases transparency and reduces the possibility of damage
defined the 17 sustainable development goals recommended to goods [13].
by Member States [10], one of which is closely linked to IoT.
[11] 3.2 Warehouses Based on Cyber-Physical System
Past trends have transformed traditional approaches to
business and sustainability management into a modern Innovations that occur within industry 4.0 create new
approach based on technologies developed alongside the technologies that facilitate system management. The Cyber-
development of needs for a different approach and Physical System (CPS) can track and create a virtual copy of
environmental protection relationship. the actual process that can be used to monitor process
performance. In addition, the CPS is very similar to the IoT
3 REVIEW OF RESEARCH concept that allows all components within the system to
communicate with one another i.e. that the physical
The topic of sustainable logistics and the IoT has often components are virtually connected, allowing for cost
been explored and there is a considerable number of papers savings in parallel with increasing efficiency. But, there is
that closely deal with this topic, especially the impact of the one big difference between the CPS and the IoT. The CPS is
IoT on warehouse and logistics systems. However, there are only focused on physical objects while it may be focused on
many of research papers that address the topic of the impact creating network of things that are focused to service

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 Krešimir BUNTAK et al.: INTERNET OF THINGS AND SMART WAREHOUSES AS THE FUTURE OF LOGISTICS

providing. Warehouses based on this technology include sources, energy-efficient building materials which, by their
RFID sensors, Bluetooth technology, Wi-Fi access points, construction, are insulators, improvements in logistics supra-
cameras and robots that are coordinated in the system to structure by improving the forklift, by installing automatic
perform a defined task. The role of a man in such a warehouse closing doors, etc. [18] On the other hand, Amith and
is primarily related to monitoring and reprogramming the Harrison (2013) emphasize that ecological acceptance of the
system if necessary. However, the CPS technology also storage system is ensured through awareness of the impact of
enables inter-machine co-operation between robotic systems, such a system on the environment and suggest a warehouse
thus reducing the need for human work. Such designed design that will maximize the use of natural lighting, water
robotic systems also enable human movement to recognize supply and wastewater management systems, noise reduction
what enables employees to use robotic help in carrying out to the surrounding community and improved temperature
activities. [14] By replacing human labor with automated and control. [19]
robotized systems, or through the implementation of such The transformation of the traditional logistics system
systems as humanitarian aid, the efficiency of the warehouse into the environmentally sustainable results in the
system increases. Activities that are dangerous for a man can improvement of all elements of sustainable development.
be robotized, thus reducing the risk of injury and unlucky Reducing costs increases funding available to improve
cases. ecological acceptability, which also affects the social
component of sustainability. Furthermore, through the
3.3 IoT Conducted Inventory Management optimization of the commissioning route through the WMS,
it affects the performance that the logistics processes
The possibilities of using the IoT technology are growing develop, that is, their efficiency, which ultimately results in
in parallel with innovations. In the context of warehousing greater sustainability. [18]
systems, the IoT allows the connection of previously Many authors point out that logistics is one of the
unreliable physical components to the network, thus fundamental components that needs to be paid particular
managing the storage facility and facilitating it. Particularly attention, especially in large cities where it is timely
problematic components of each warehouse are inventories supplying the necessary resources, crucial to the
and operations associated with their management. development of all processes inherent in cities. [20] Robotics,
Traditional systems in most cases include manual automation, electrification, sensing as well as the application
manipulations of inventory as well as inventory management of the IoT technology, the storage system is managed more
based on human. However, by deploying sensors and linking efficiently, which reduces the negative impact on the
them to the network, sensors can look at real-time inventory, environment.
which greatly facilitates their management. Therefore, the
new warehouse system is based only on IT with human as an 3.5 Future of Warehouse Systems
operator that only controls the process. This approach is
based on RFID technology, which is the basis for deploying By implementing technologies of Industry 4.0, such as
and using this approach. [15] The IoT and RFID technology the IoT, warehouse systems become more efficient and their
not only simplify inventory deployment, but anticipate future performance is improving. By automating warehouse
orders, tracking product durability, temperature, humidity in operations, the warehouse system becomes less dependent
the air, and other parameters that could affect product and responsive to human work variability. By applying
damage. RIFD technology is the foundation for the autonomous systems in transportation, transshipment-
functioning and development of the IoT system. [16] The loading operations, and operations of palletized goods to
application of RFID technology in warehouse management warehouse regal, the flow of goods through warehouses
has a number of advantages that primarily relate to increasing becomes more fluent. However, autonomous systems must
efficiency, accuracy and updating of information, as well as be tailored to the storage environment to minimize the risk of
tracking stocks and inventory losses. [17] By implementing collisions. Existing autonomous systems in a large number of
the IoT and RFID technology in organization’s storage cases, by having a barrier remain standing in place, that is,
systems, they provide competitive advantage based on lower they can only move through previously defined and narrowly
operating costs and greater efficiency of the process. restricted corridors. [21]
A potential solution to such and similar problems of
3.4 Impact of Warehousing on the Environment implementation is the development of artificial intelligence
that is capable of making decisions similar to man-made
Warehousing, just like logistics, is an activity that decisions. Robotic systems with artificial intelligence enable
generates a certain amount of greenhouse gases. Poor energy making simpler decisions and adaptation to new
efficiency of warehouses as well as environmentally circumstances in the environment. [22] As such, artificial
unacceptable heating, air conditioning or lighting systems are intelligence is already present in a number of daily-used
just some of the factors that affect the amount of carbon technologies such as internet browsers as well as systems for
dioxide discharged. In order to increase the ecological predicting earthquakes and weather conditions. [23] The
acceptance of storage processes, Đukić, Česnik and Opetuk Deep Learning concept moves artificial intelligence and its
(2010) propose the implementation of energy-efficient application to a higher level through the ability of such
lighting, the production of electricity from renewable energy systems to learn and improve their knowledge without the

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need for human intervention. [24] The necessity of 4 CONCLUSION

developing new warehouse management technology and
automation of warehouse operations is growing with Almost all organizations operating in today’s market are
increasing storage space size. The potential for warehouse affected by the development of the Internet. [15] The
technology development is growing with the drop in the development of the Internet is also developing technologies
number of workforce available, which is one of the problems related to it, such as the IoT. Therefore, it is appropriate for
that EU countries face. [21] Increasing the demand of the the development and implementation of the IoT technologies
interested parties and market growth is one of the conditions to be in the focus of today’s logistics industry and the
that are placed on storage systems, which is their flexibility improvement of warehouse systems. [35] The imperative to
and sensitivity to the requirements set. [25] Theresponse to deploy industry-based 4.0 technologies stems from the
such requests is often seen through the implementation of requirement to maintain an organization’s competitiveness.
smart technologies that improve storage processes. One Organizational completeness may be increased whit
example of technology is glasses that signal an employee an implementation and upgrading of the existing WMS to
item to take [26]. Further, the challenges facing storage advanced IT solutions as well as through the implementation
systems in the future are the reason why an increasing of solutions, technologies of industry 4.0 like it, Big Data,
number of organizations become virtual, allowing customers sensors, robots etc. [36]
to create orders online and request that the purchased product By developing different organizational forms such as e-
be delivered to the required location [27]. organization, the challenges and requirements encountered
The implementation of a large number of sensors by storage systems are growing. One of the ways of adjusting
generates a large amount of information and data stored on is the automation and robotization of the warehouse system.
the foreseen servers. The Big Data Concept is a new Robotization does not mean completely replacing human
paradigm for warehouse systems and organizations, enabling work with machines, but increasing the efficiency of human
tracking and prediction of customer orders, resulting in easier work with robotic systems. [37] The use of robots in
stock management. [28] However, the implementation of warehouses also means the possibility of increasing the rate
smart systems as a result has some challenges and risks that of picking from warehouse shelf using the fastest or simpler
need to be adequately managed. route of movement, thus reducing total costs [38], and
One of the underlying challenges of warehouses based possibly by improving existing WMSs in warehouse systems
on industry 4.0 is their security. Security problems are related that regulate and set up an order picker’s route. Existence and
to risk of lack of data. Security problems are also related to level of warehousing system competitiveness depends on
the security on the Internet generally because all their ability to adapt to new technologies as the ability to meet
communications are based on an internet connection. This is customer requirements.
explicitly related to the storage systems that have Big data This secondary research found that industry 4.0 has a
databases implemented. The existing encryption methods are significant impact on warehousing operations, which are
no longer sufficient to ensure a satisfactory level of security. becoming more efficient by implementing technology such
Likewise, there is a lack of adequate software solutions for CPS, it and other industry-based 4.0 technologies. Future
managing, analyzing, and printing such a large number of researchers are advised to conduct a primary survey aimed at
data. [29] Stealing or releasing information stored in identifying the number of warehouses that use Industry 4.0
databases as a result may have disruption of user privacy technologies as well as identifying the type of technology
[30], i.e. logistic customer service. Because of the simplicity, they are using.
convenience, speed and ease of logistic organization, they
decide to use cloud computing technology that places data on 5 REFERENCES
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Authors’ contacts:

Krešimir BUNTAK, Ph.D. Assoc. Prof.

Corresponding author
University North,
Trg dr. Žarka Dolinara 1, 48000 Koprivnica, Croatia
krbuntak@unin.hr

Matija KOVAČIĆ, B.Ec.

University North,
Trg dr. Žarka Dolinara 1, 48000 Koprivnica, Croatia
matkovacic@unin.hr

Maja MUTAVDŽIJA, B.Ec.

University North,
Trg dr. Žarka Dolinara 1, 48000 Koprivnica, Croatia
mamutavdzija@unin.hr

TEHNIČKI GLASNIK 13, 3(2019), 248-253 253

ISSN 1846-6168 (Print), ISSN 1848-5588 (Online) Subject review
https://doi.org/10.31803/tg-20180810113043

ASSESSMENT OF THE EFFECT OF INTEGRATION REALISATION IN CONSTRUCTION

PROJECTS

Roman TRACH, Marzena LENDO-SIWICKA, Katarzyna PAWLUK, Nina BILOUS

Abstract: The aim of the article is to develop an assessment model for the effect received from the integration of enterprises during the realization of investment projects in the
construction. Having analysed the existing methods of the economic effect evaluation, we came to the conclusion that it is impossible to use them completely to assess the
economic effect of the integration of enterprises during the investment projects in the construction. In the case of an integrated realization of a project in the construction sector, it
is the information and communication links that are combined, and not the enterprises themselves. In addition to that, not all models take into account the synergistic effect. To
solve the above-mentioned problem, we analysed the advantages gained by participants during the realization of the integrated project in construction and the benefits that have
the greatest impact on the synergy effect. The calculation of the effect of the information and communication system management and the innovative nature of the process of its
implementation suggest that this process has a clear investment component. Consequently, the process of enterprise integration should be considered as an investment project
implemented at the level of network association.

Keywords: construction project; information and communication system; integration; synergetic effect

1 INTRODUCTION

The questions of cooperation and integration during the

delivery process were a great concern of scientists for a long
period. For instance, it recalls how the separation of the
design and construction phases of projects was identified as
a problem by government industry reports in the UK as early
as 1962 by Emerson, who identified how removed the
responsibility for design is from the responsibility of
production [1]. He suggests that the procurement models
which omit the contractor can increase risk, reduce
communication between team members, cause delays and
create incorrect information which can lead to disputes and
claims. The importance of the integration processes was
emphasized by Chinowsky [2] who developed what is called
an "Integration Matrix" (Fig. 1). Figure 1 Chinowsky's integration matrix

Figure 2 Levels of integration in construction

The four quadrants of the matrix refer to the varying high. They note that this is the preferred state for
levels of trust and communication. The final state is that of collaboration to occur. The concept of high performance is
integration, where both trust and communication levels are routinely implemented in diverse industries but has received

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 Roman TRACH et al.: ASSESSMENT THE EFFECT OF THE INTEGRATION REALISATION IN CONSTRUCTION PROJECTS

little attention in the construction industry, where success is characteristics affords ground for affirming or denying the
typically measured using traditional indicators, such as time, existence of a network structure. In our opinion, it is the
cost and quality. Authors suggests that the problem can be interrelationships that can be distinguished from the general
addressed by viewing the construction team as an integrated system of elements and can be used as the basis for
group of participants within a network, rather than as a group identifying the network organizational structures. This is
of participants. The team needs to consist of a cohesive especially important for the network structures of the
network where members focus on building long term investment and construction complex, since they are
relationships that are transferred from activity to activity. characterized by the absence of legal consolidation of
The project delivery method is selected by the owner of integration relationships, such as participation in capital, the
the construction project. That method establishes the transfer of property rights between economic entities.
preconditions for the realization of the project, such as the The effect of network interaction between enterprises has
roles and responsibilities of the participants, including the its own specifics. It is not only the effect of consolidation
legal agreements between the parties by setting the project because enterprises retain some independence (there is no
target and payment method. This tends to be a critical factor saving in management costs, for instant, because the
so if selected correctly, it enables the successful management apparatus of each of the enterprises remains the
implementation of a construction project. Fig. 2 shows three same). At the same time, a systemic dynamic should arise in
levels of integration in construction. the process of interaction and should become the
The aim of the article is to develop the assessment model consequence of it. It means that the coordinated work of
for the effect received from the integration of enterprises independent companies provides an additional synergetic
during project delivery in construction. effect of the system interaction as a whole.
The investigation of the synergy phenomenon began to
2 MATERIALS AND METHODS develop with the activation of integration processes in the
economy, although the very point of the synergetic effect was
Network structures have different configurations described by Aristotle. In the IV century BC, he noted that
including heterogeneous elements that provide the highest "the whole is greater than the sum of its parts" [3]. I. Ansoff
level of collaboration. Such elements in each particular case defined the synergy effect as the possibility of getting the
have their own unique list that provides the energy of better economic effect from the joint work of several
cooperation in each particular situation. The overall business units in comparison with the results of their
economic effect depends not only on the elements the independent activity [4]. In his concept of synergy, he
network consists of, but also on the nature and quality of the focuses on the role the economic base has, on the potential of
links between them. material and non-material assets and their close connection
In modern economic conditions, the decision on the with the potential of the enterprise.
economic agents’ integration considerably allows the change X. Itami considered that the synergy effect received from
of the competitive position of the enterprise. The integration integration is a result of resource utilization efficiency and it
process leads to new subsystem formation and the is growing in an integrated corporation in comparison to their
interconnections between them. At the same time, the use by companies before integration [5]. He identified two
interaction and influence of the subsystems in an integrated types of resources: physical resources (fixed assets,
structure is characterized by the emergence of a new inventories, etc.) and intangible assets (brand, technology
synergetic component, which is considered to be the effect of and know-how, corporate culture, etc.). In his opinion, two
enterprise integration, and is the basis of the goals and types of effects can be formed as a result of integration:
motives of integration. The synergistic effect presence means - complementary effect which refers to the improvement
that the result of the integrated system of enterprises is higher of physical resources usage (the corporation uses its
than the sum of the results of individually operating resource potential in full),
enterprises united in the process of integration. Depending on - synergetic effect which is achieved only by using
synergy effect it can evaluate the effectiveness of the invisible assets.
integration itself.
The efficiency of the integration process depends largely In our opinion, using a network organizational structure
on how effectively the management of various forms of during the delivery process in the construction industry has
interaction between construction enterprises is carried out. the most interesting and at the same time the most difficult
The results of the integrated enterprise's production processes issue to study. It is the issue of information synergy
are not always clear and, in some cases, can lead to an evaluation that is formed due to the optimization of
efficiency decrease, because the enterprises do not fully use information and communication management.
the potential of business units’ interaction and the additional The analysis of theoretical and practical research in the
effects are the results of such potential. If the interaction of field of economic entities integration [6, 7, 8] showed that the
enterprises within the framework of integrated structures efficiency of integration is mainly assessed by minimizing
does not provide the desired effects, it is important to update the costs of the enterprises (they are transactions in most
the methodological approaches that help improve the cases). In this article, only this approach is not sufficient,
mechanism of the integrated structures management. The since it is planned to assess the efficiency of integration not
presence or absence of economic connections with certain only from the position of the interacting entities themselves,

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 Roman TRACH et al.: ASSESSMENT THE EFFECT OF THE INTEGRATION REALISATION IN CONSTRUCTION PROJECTS

but also from the position of the whole integrated system, The value in Vij – (Vi + Vj) is a synergistic effect. To
within the framework of their interests and its coordination. recoup the integration, this effect should be greater than the
It is expedient to assess the "cumulative effect" of acts of sum (P + E).
initiating integration chains of interaction between the socio- Methods that are used in the framework of the
economic entities during project delivery in construction. comparative approach make it possible to compare the
Such effect can be evaluated only within the framework of a assessed object with similar objects and on this basis, to
synergetic approach to integration evaluation. establish its value. A comparative approach can be used for
Synergy can be classified according to the impact on the both market valuation and the valuation of investment value.
company's cash flows [9, 10] (Fig. 3). However, since there are no two absolutely identical
associations, some average market multipliers are expertly
determined and used to calculate the cost using comparative
approach methods and that reduces the accuracy of the
results.
In practice, the Capital Assets Pricing Method is used
more often and it gives the most objective assessment of the
effect received from the integration. In this approach, the
discounted cash flow method is used to estimate the value of
the company. The very core of the method is to determine the
current value of cash flows that will be received in the future.
In the framework of the Capital Assets Pricing Method, there
are a significant number of models suitable to calculate the
economic effect.
In particular, S. A. Orekhov [15] calculates the effect
received from integration into the holding structure as
follows:

Figure 3 Classification of synergy C

= D(PN ) n + D(PA) n + (EE ) n − DI n + DTn − I o (2)
n

One of the main methods for synergistic effect

Where: n - the calculated period of time; D(PN)n - the
evaluation is to compare the value of integrated enterprises,
additional profit received from activity expansion; D(PA)n -
before and after their combination [11-13]. Net Assets Value
the additional profit taken from risk reduction due to the
Method, Market Method and Capital Assets Pricing Method
diversification of the holding's activities; (EE)n - the saving
can be used in this case. The Net Assets Value method is
current production costs; DIn - the additional investments for
often used in takeovers and mergers and includes a set of
reconstruction and expansion; DTn - the increase (saving) of
methods to assess the value of enterprises, based on the costs
tax payments; Io - the investments at the time of takeover.
that are necessary to restore the object of takeover. The main
A number of authors [16] propose to use the method of
principle on which this method is based is the principle of
discounted cash flows in the framework of this approach. The
substitution. It means that the buyer will never acquire an
synergistic effect is calculated in accordance with:
object at a price exceeding the cost of acquiring or
reproducing an object similar in its consumer characteristics. T
This approach does not allow taking into account the changes ΔCFt
S =∑ t
(3)
in performance indicators in future periods. A typical t =1 (1 + R )
example of the net assets’ value method is the method
proposed by A. Damodoran, who determines the synergetic Where: ∆CFt - the difference between the cash flows of the
effect as a result of exceeding the value of integrated integrated company and the amount of cash flows of each
companies over the sum of the companies' value before company separately before the time t; R - the mathematical
integration [14]. In particular, the Net Acquisition Value, discount factor expectation that is calculated according to the
NAV, is calculated according to the following formula: planned rate of return to the net worth of the company that is
taken over.
NAV = Vij − (Vi + V j )  − (P + E ) (1) The increase in cash flows is as follows:

Using the following notations: Vij - the value of the combined

ΔCFt = ΔRt − ΔCt − ΔTt − ΔI t (4)
firms i and j; Vi - the value of the standalone firm I; Vj - the
value of the standalone firm j; P - the premium paid for the Where: ∆Rt - the increase of the income received from the
acquisition; E - the amount of expenses engaged in the takeover; ∆Ct - the increase in costs; ∆Tt - the increase in tax
acquisition process. payments; ∆It - the increase of additional working capital
investments and fixed assets.

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Having analysed the above methods and approaches, we effects that are indicative for the integrated project delivery
can conclude that they cannot be fully used to evaluate the in construction. Taking into account the specifics of this
effect received from enterprise integration during project research, namely, the evaluation of the effect formed after the
delivery in construction, since the vast majority of these information and communication system introduction in the
methods are based on the analysis of enterprise integrated project delivery in construction, we can identify
amalgamation and their cash flows after the takeover. In the the following synergistic effects:
case of integrated project delivery in the construction
industry, it is the information and communication links that I t = ∑ ΔS = S1 + S2 + S3 + S4 + S5 + S6 (6)
are united, but not the enterprises themselves. Additionally,
the synergistic (immaterial) effect is not taken into account
Where: ΔS - the synergy effect, which is formed from the
in all models. Moreover, it is necessary to distinguish more
introduction of the information and communication system
clearly between the terms of economic effect evaluation and
in the integrated project delivery; S1 - the synergetic effect
integration and the synergetic effect which is one of the main
formed from reducing the number of errors and collisions in
factors, but not the only one.
the construction project delivery; S2 - the synergistic effect
from the overall reduction of project duration due to a higher
3 RESULTS AND DISCUSSIONS
coordination of actions; S3 - the synergistic effect of
transaction costs reduction; S4 - the synergetic effect from the
This article proposes, in the framework of the synergetic
cost reduction at the stage of facilities’ management; S5 - the
approach, to take the ratio of the additional income received
synergistic effect of a new value creation; S6 - the synergistic
from the association of enterprises to the costs on this project
effect from the production scale increase.
delivery as a criterion for the economic efficiency of
The next stage is the analysis of the cost structure
enterprise integration programs.
connected with the integrated project delivery. The expenses
The calculation of the economic effect received from
can be divided into two parts, the sustainable (investment)
managing the information and communication system and
and variable (operational) costs.
the innovative character of the process of its implementation
The structure of investment expenses is determined by
shows that this process has a clear investment component.
the task to introduce the integrated model into the network
Therefore, the process of enterprise integration should be
organizational structure of enterprises and is as follows:
considered as an investment project delivered at the level of
a network association. Accordingly, regarding the innovative
process of the information and communication system  y 
CI=
t  ∑ (Ce ∗ Ts bas + Cst ) + CI ce + CI s + CI db  +
network model realization, the predictive efficiency of  i =1 
investments can be expressed by the following economic and (7)
j
mathematical dependence: + ∑ (Cas ∗ Tadapt )
i =1
m
It
∑ (1 + n )t Where: Ce - the average wage rate of an employee who is
i =1 t
Et = m m
(5) having the training; Ts.bas - the time of training, one employee
CI CO coordination and workplace integration; Cst - the average cost
∑ (1 + nt )t + ∑ (1 + nt )t
=i 1 =
t i 1 t of training; CIce - the investment costs for computer
equipment acquisition; CIce - the investment costs for
Where: Et - the efficiency of the information and software acquisition; CIdb - the investment costs for database
communication system operation in the integrated project acquisition; Cas - the average wage rate of the project
delivery over a period of time; It - the total revenue stream manager assistant; Tadapt - the time the assistant needs to
that the integrated enterprise receives from the information adapt in an integrated system; y - the number of employees
and communication system implementation over a period of and workplaces integrated into the system; j - the number of
time; CIt - the investment costs that the enterprise spends to the project manager "assistant".
launch and implement the integrated information and As it is seen from the expression (7), investment costs
communication system; COt - the operational costs to can be divided into the following three groups:
manage the information and communication system of the 1) the costs of training for the employees to learn the new
business entity; t - the analysed period of time; nt - the rate innovative model of network relationships (including
of discounting accepted for calculations; m - the number of both the costs of pay for those who conduct training and
enterprises that integrate. the loss of time during the training period when the
The synergy effect calculation is the most difficult part employees of the enterprise are not engaged in the
in the total revenue stream calculation. It is possible to use performance of their immediate duties);
various factors to assess the synergy, and their sum-total is 2) the expenses for the computer equipment, software and
formed according to the direction and the logic of the database acquisition and adaptation;
research. Therefore, it is a situation similar to the economic 3) the costs to adapt the project manager assistant to the
efficiency integration evaluation, namely the isolation of the integrated system.

TEHNIČKI GLASNIK 13, 3(2019), 254-259 257

 Roman TRACH et al.: ASSESSMENT THE EFFECT OF THE INTEGRATION REALISATION IN CONSTRUCTION PROJECTS

The first two groups of expenses are reflected in the COs - the operating costs for software maintenance; COdb is
formula (7) in square brackets and include the training, the operating costs for database maintenance; Tw - the project
computer equipment, software and database acquisition for manager assistant work duration; Ts.add - the time for
all employees participating in the integrated process. The additional training, consultation and formalization of
third term presents the expenses for the project manager knowledge for the employee; x - the number of employees
"assistant". who need additional training and consultations.
Operating costs are given in the following expression: m - the duration of the project, years.
They also form three clear groups:
y j 1) expenses for computer services, software and
CO
= t ∑ (COce + COs + COdb ) + ∑ (Cas ∗ Tw ) + database maintenance;
i 1 =i 1
(8) 2) expenses for the salary of the project manager
x
assistant;
+ ∑ (Ct ∗ Ts add )
3) expenses for the additional training, consultations
i =1
and formalization of knowledge for employees.
Taking into account the expressions (6)-(8), the formula
Where: COce - the operating costs for computer services;
(5) can be expressed by the following economic-
mathematical dependence:

m
S1 + S2 + S3 + S4 + S5 + S6
∑ (1 + nt )t
i =1
Et = (9)
 y  j y j x

m  ∑ (Ce ∗ Ts bas + Cst ) + CI ce + CI s + CI db  + ∑ (Cas ∗ Tadapt )

m ∑ (COce + COs + COdb ) + ∑ ( C as ∗ Tw ) + ∑ (Ct ∗ Ts add )
∑  i 1
i 1=
(1 + nt )t
=i 1
+ ∑ =i 1 =i 1
(1 + nt )t
i 1= i 1

The predictive efficiency indicator Et of the information Abbreviations

and communication structure integration during project
delivery in construction should not be less than one. At the NAV - Net Acquisition Value
same time, the value Et > 1 indicates a positive effect of ERP - Enterprise Resource Planning
innovation. BIM - Building Information Modelling

4 CONCLUSIONS 5 REFERENCES

A system of economic and mathematical dependencies [1] Mosey, D. (2009). Early contractor involvement in building
has therefore been formed to assess the effect of enterprise procurement: contracts, partnering and project management,
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[2] Chinowsky, P. & Songer, A. (2011). Organizational
is the ratio of the additional income received from the management in construction, New York: Spon Press.
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sustainable (investment) and variable (operational) costs on management). Sankt-Peterburg: Piter (in Russian).
this project delivery. The paper proposes how to solve the [5] Asaul, A. N. & Ivanov, S. N. (2008). Snizhenie
issue of separating the share, which is formed as a result of transaktsionnyih zatrat v stroitelstve za schYot optimizatsii
informatsionnogo prostranstva (Decrease in transaction costs
integration processes, from the general effects of the
in construction due to optimization of the information space).
enterprise's economic activity. Finally, the advantages Sankt-Peterburg: ANO IPEV (in Russian).
obtained by the participants of the integrated project in [6] Rowley, J. (2002). Synergy and strategy in e-business.
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greatest impact on the synergistic effect are highlighted. In https://doi.org/10.1108/02634500210431603
our opinion, it is warranted to use projections to make a [7] Franzsen, D., Van der Merwe, R., Buys, S., Bischoff, A.
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project delivery in construction. Synergies within Barloworld. Unpublished manuscript,

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 Roman TRACH et al.: ASSESSMENT THE EFFECT OF THE INTEGRATION REALISATION IN CONSTRUCTION PROJECTS

Barloworld Executive Development Programme, Gordon

Institute of Business Science, Johannesburg.
https://doi.org/10.1111/j.1745-6622.2009.00255.x
[9] Baldi, F., & Trigeorgis, L. (2009). Assessing the value of
growth option synergies from business combinations and
testing for goodwill impairment. Journal of Applied Corporate
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[10] DePamphilis, D. (2010). Mergers, acquisitions and other
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[11] Sehleanu, M. (2015). Creating or destroying value through
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[12] Hamza, T., Schaier, A., & Thraya, M. H. (2016). How do
takeovers create synergies? Evidence from France. Studies in
Business and Economics, 11(1), 54-72.
https://doi.org/10.1515/sbe-2016-0005
[13] Shaver, M. (2006). A paradox of synergy: contagion and
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https://doi.org/10.5465/amr.2006.22527468
[14] Damodaran, A. (2005). The value of synergy (working paper),
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https://doi.org/10.2139/ssrn.841486
[15] Orekhov, S. A. (2001). Statisticheskie aspektyi issledovaniya
diversifikatsii korporatsiy [Statistical aspects of research of
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Russian).
[16] Basmah, A. Q. & Rahatullah, M. K. (2013). Financial synergy
in mergers and acquisitions in Saudi Arabia, Finance -
Challenges of the Future Yea, XIII (15), 181-192.

Authors’ contacts:

Roman TRACH, PhD

Warsaw University of Life Sciences,
Nowoursynowska 166, 02-787 Warsaw, Poland
roman_trach@sggw.pl

Marzena LENDO-SIWICKA, PhD

Warsaw University of Life Sciences,
Nowoursynowska 166, 02-787 Warsaw, Poland
marzena_lendo_siwicka@sggw.pl

Katarzyna PAWLUK, PhD

Warsaw University of Life Sciences,
Nowoursynowska 166, 02-787 Warsaw, Poland
katarzyna_pawluk@sggw.pl

Nina BILOUS, PhD

National University of Water and Environmental Engineering,
11 Soborna, 33028 Rivne, Ukraine
n.m.bilous@nuwm.edu.ua

TEHNIČKI GLASNIK 13, 3(2019), 254-259 259

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[4] Amidzic, O., Riehle, H. J., & Elbert, T. (2006). Toward a
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players. Journal of Psychophysiology, 20(4), 253-258.
https://doi.org/10.1027/0269-8803.20.4.253
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[7] Miller, J., & Smith, T. (Eds.). (1996). Cape Cod stories: Tales
from Cape Cod, Nantucket, and Martha's Vineyard. San
Francisco, CA: Chronicle Books.
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https://doi.org/10.4128/9781606492147
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