COLLEGE OF ENGINEERING
DEPARTMENT OF MECHANICAL & INDUSTRIAL ENGINEERING
LAB REPORT COVER PAGE: MECHATRONICS M2H324731
Student Name
Alaa said aljabri
Student Number
Programme POM 130199
30 / APRIL/2019,
Experiment No. 4 Date of Experiment
Sem B
Name of Experiment
APPLICATION OF STRAIN GAUGE
Instructions to the students:
1. All reports must be computerized with handwritten(scanned) circuit diagrams, drawings,
figures, graphs and signal flow.
2. Plagiarism is a serious offense. In case of any plagiarism detected, penalty will be
imposed leading to zero mark and malpractice.
3. Coursework reports should be written individually.
4. Coursework reports should be submitted on time, and submission after deadline will be
capped as per college policy.
5 Every report must be submitted ON-LINE thru Turnitin assignment.
Mechatronics (M2H324731) AY 2018 -2019 Semester B
M&IE Department
I. Aim & Problem Description
verify the accuracy of electrical resistance strain gauge .
problem description:
Application of strain gauge (cantilever beam) this application describe the
different between the theoretical and actual strain gauge by using different value
of the load which is 0,5,10,15,20,25 and 30 (N) and put thus load in the front of
the cantilever beam to determine the value of the increasing load in µε for each
different load respectively then repeated from 30,25,20,15,10,5 and 0(N)to
determine the increasing load in µε respectively and finally get the actual strain
reading, otherwise the cantilever beam is fixed with resistance which is called
electrical resistance strain gauge in 120Ω is fixed on the surface of the cantilever
and the length of cantilever beam is 150 mm and the base and height of the
cantilever beam is 25.4mm and 3.2mm in order ,this is the application of the
strain gauge .
FIGURE 1: APPLICATION OF THE STRAIN GAUGE
ELECTRICAL RESISTANCE.
II. Tabulation of Results
Loa Actual Strain Gauge Theoretic %Error %Resistan
d al (Actual ce change
(N) Increasin Decreasin Averag Strain Vs (Ω)
g Load g Load(N) e (µ) Theoretic
(N) Strain( al Strain
N)
0 0 80 40 0 0 0
5 250 310 280 250.743 11.668 0.053
10 550 600 575 501.487 14.659 0.106
15 810 850 830 752.230 10.338 0.159
20 1100 110 1100 1002.974 9.673 0.212
Mechatronics (M2H324731) AY 2018 -2019 Semester B
M&IE Department
25 1350 1350 1350 1253.717 7.791 0.265
30 1510 1510 1510 1504.461 0.368 0.318
III. Calculations
Average Strain = (Decreasing Load – Increasing Load)/ 2
Average strain = (80-0)/2=40(N)
P, Load applied on the cantilever in (N)
b, Base of the cantilever =25.4 mm
d, Height of the cantilever =3.2mm
ε , Strain gauge in (µ)
E, Modules elasticity =69000N/mm2
L, Length of the cantilever beam =150mm
ε= (L * P *6*10^6)/Ebd2
= (150*5*6*10^6)/ (69000*25.4*(3.2) ^2)
= 250.743µ
%Error = ((Actual strain – Theoretical strain)/ Theoretical strain) ×100
= ((280- 250.743)/ 250.743) ×100
= 11.668%
∆R, change of resistance Ω
R, Electrical resistance of strain gauge =120Ω
GF, Gauge factor = 2.12
ε, Theoretical strain gauge
∆R= GF*ε*R*10^-6
=2.12*250.743*120*10^-6
=0.0637Ω
%∆R= (∆R/R) ×100
= (0.0637/120) ×100
0.0535% =
Mechatronics (M2H324731) AY 2018 -2019 Semester B
M&IE Department
IV. Graphical presentation
V. Components and its specific functions
FIGURE 2: EQUIPMENT WHICH IS USED
TO MEASURE THE ACTUAL STRAIN
GAUGE
Mechatronics (M2H324731) AY 2018 -2019 Semester B
M&IE Department
I. Discussion, and Conclusion
The strain gauge as instrumentation which is used to measure the
parameters such as length, displacement and weight. When the strain
applied to the materials or when the strain stretched is effected to
change the electrical resistance. Otherwise Thus change of the
resistance is used to measure the force which is applied to the
cantilever beam, this device is called strain gauge.
FIGURE3: STRAIN GAUGE
In addition, the working principle of the strain gauge is understanding WHICH IS USED TO MEASURE
THE DEFORMATION
When studying the strain gauge load cell is working and what the
effectiveness of the electrical resistance strain gauge and the load whatever is
happening under applied the force in the front of cantilever beam. Otherwise this
transducer once applied the load or the force weight it cause to make the change
into electrical signal output this is proportional to the force weight or the load applied
, moreover when the is placed in the front of the cantilever beam it will make
deformation in the dimension of the underlying strain gauge, so this deformation is
creating the changes in the electrical resistance strain gauge when the change of the
electrical voltage , thus voltage it gives the proportional relationship with the load
applied , by the way there are different type of the strain gauge is depended to the
working principle for each strain gauge such as mechanical, electrical and
piezoelectric.
Furthermore, the significance of the gauge factor which is are
the parameter is used to measure the change in electrical
resistance to the change in the length of strain gauge and the
range of the gauge factor is 1≤GF≥2 in this rang the gauge
factor is required for the strain gauge.
FIGURE 4: PIEZOELECTRIC
STRAIN GAUGE
In the conclusion, the percentage of the accuracy of the strain gauge is depending of
the bridge force ,gauge sensitivity and the strain gauge pasting method so in this
experiment verifying the percentage of the accuracy of the strain gauge which is
between 7-12 % in this range which is getting in this experiment otherwise the
relationship between the strain gauge and the load or force weight is proportional
relationship ,when the force weight applied increase the strain gauge will increase
under the change of the resistance and the length of the cantilever beam.
Mechatronics (M2H324731) AY 2018 -2019 Semester B
M&IE Department
Reference:
Croser, P. & Ebel,F., 2002.STRAIN GAUGE, Basic level, , Festo Didactic
GmbH & Co., [Online] Available
from:http://www.festodidactic.com/ov3/media/customers/1100/093131_lesepro
be_web.pdf[Accessed 30th April 2019].
Chris,S.,2012.THE LOAD CELL. Hoboken:Taylor and Francis [Online]
Available from: http://site.ebrary.com/lib/alltitles/docDetail.action?
docID=10639939 [Accessed 3th may2019].
Andrew,P.,2011.relationship of the strain gauge: A technician’s and engineer’s
guide. 3rd edition. A Boston:Butterworth-HeinemannTitle[Online] Available
from: http://site.ebrary.com/lib/alltitles/doc Detail.action?docID=10440528
[Accessed 4th may 2019].
Ian,T & Institution of Plant Engineers,2014.Engineering Applications of strain
gauge , Abingdon:Routledge. [Online] Available from:
http://site.ebrary.com/lib /caledonian/docDetail.action?docID=10127894
[Accessed 16th april 2018].
Quia.com , 2019 . [Online] Available from:
https://www.quia.com/files/quia/users/sfah6922/Basicstraingagues2011.2012/
ATM1132_Basic_strain-gauges_module_9_student_version.pdf. [Accessed 5 th
May 2019].
Mechatronics (M2H324731) AY 2018 -2019 Semester B
