0% found this document useful (0 votes)
71 views27 pagesZess Han
Uploaded by
ujjwal kumarCopyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
Available Formats
Download as PDF or read online on Scribd
0% found this document useful (0 votes)
71 views27 pagesZess Han
Uploaded by
ujjwal kumarCopyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
Available Formats
Download as PDF or read online on Scribd
/ 27
C pees Vee Real
Fz very) or Boys
taenet tea
Plattue gone
NATIONAL INSTITUTE OF TECHNOLOGY, JAMSHEDPUR
END SEMESTER EXAMINATION (0% 99 2927)
CLASS: BT HH (Vl SEMESTER) SE ULL MAK
BRANCH: MET. AND MAT. ENGG LM ¥
TIME: 3 HOUR CREDIT: ¢
vararro3 SUBJECT: Creep fatigue & Fracture
INSTRUCTIONS
I, Aiewspt all the questions: Missing ant, If ny, may be arsumeut sultably
1 <(~ Tensile strength is used as de won for brittle materinls, Justify the statemen '
- Name the types of ractury absueved fa maletlal due to terisile Tond '
es e stress-strain diaggany As of lite signifiinice in faite onhy=ie Wl '
TED- Grits equation fe fimeture dows not apply for metals. Why !
EE Nome various stops iavolved iit Skeavage tracnire H
Be Ba SS gE Serve TH era aT AeA? f
fo TH Dr N curve for Aluminium: Copper and ae. >)
i) (ine he condition for pininteaio fracture oughness,§ @ = 2 (Ae t
©5) Draw Aol va AX Carve and tate! various region and paris tn it.
> (8) Shot ts the effect of small defee' serack an deforination behaviour of any 1°!
2 wm wwe the various stages in fatipue provess? Explain wood's euneept of microdefurmat:
Joan t0 formation Of fatigue ernek.
WD The expected plain strain tractury tougiinessof @ materlal is 60 MPa Whot is miniin
thick ogh8 OF Ue material? (© yy = 1200 MI is
2 The 0 wonure toughness ( A’x:) of magnesia stablized zirconia is MPR" ° |
pene! of this material fs foxdeu tv this fovel of strcas without failure, date
peace
‘lave sizé that op WM have been prebent. {The content fe unity, Teaslle strength is 130 Ghat
3G) Explann te term*Oe formation Mechanism Map”, 3
ae ges x i eR Gasp chase lace at ores Ne enrss id eas ¥
(5) What ove the properties meyutect in material for turbine blade 2s
Id). Name auy ove a SROs stacey Si
4G) Eph sess covosion eracklag and Mguemetal exten 4
5 Ga) Explain with a neat sketch the conespt of plauticity coreection (plastic zune). What is plate e« s
fc tamagie wen aa
Reload iam TD etme atin ae ee.
size and the stress intensity fnetor for
ck, Asiume that the 9
oo meee ees
( Brag ° 7
Cie. ne
Qt p Q scanned with OKEN Scanner
r San
yD
ie O Tewile dewey is wpolar 0 deugu Oriteua rc bnttte
mokeuola 3, 14 ps to preclict fee osdi'y
FH tre materiel + Wt httond ang tanule forcer
before breatei~ nr fradure
Safety
WG) motrin Serechion > — —
CY) Fractme fret Aion
CY aintasmannee 2 Qoality Conhel
@ Pahl Bntte
- Sfradn Ever loo —
Ae bw —
(pw Preyin rote] WA
@ Exyg SSC | True SC
| | 20
oe
a 200 aan by
| D1 (
LS Z
Cor-pauwtively bows Steers valine
. Divnerw— on Ripper
A aS Le cy bein
Tow) (a104 ak in Ey ssc
We
A
ais
E 2 omparity Gintie Ayy)
Gi) rine reeves (THe) Neder Defes
® sppin Syene Grants, ganas) —
© Bub melaty > duetile
0) egerton of erey > Gupiter
Met => Puybe yr
7 J inert
7 Evergey Hees paborn
No COPY) coubreshon i. 5 esta snar
— ca aa ae
VW) + Reaner, ae ree
SCL SR a
Troe ES eter
ya i) ee nC
CEP
Ke \2
ry ae
SS MES (OTe Or eet
Pata
oe bys
(oe Uren
ai
Sad
Cea el
oa as
earl iae
o
a Tewsity db)
No }
ava 'y eo, ]
youn ra mr
aan, Par NG
ruse eat Gece
ia ee
COU
Ves ae _ re
oa an Ca
(he Saree serie)| BO sees a Oi coca laa
Le a IS Ta
eS
PAST Ace ra Se cee
Cals De aera
ne
Pal
ab a Nae Le aa
[or ela MALE CS TLCTCY OZ
LU OUT NT Cea
oo.
( a) ey) ()
DOCU Cg ON tno eee rarey aoe)
alas (€ tre) ( 2 nd)
ale es Sonic eel De) Pree
) aan
We Eels
Leone RN a
SG Se Ue
CCL eer hae CO)
Cea hao
anes
Oe = VBE 4102 mw
TCD AS Soa Coa SL SS
(TAKS Co SCT SANS) Sod qus nuit
Dm CC CS oR re Ue Foe LORE UEC
OREO ACS WNT CUTS UCO Ur coeur NCSC NSUN OPN er
et Me (COMET ON EON OO
a ee VAIN ON Wedron Sun
Ea ON, PET LOA ae
eS
And comer
G
a)
— Caer a)
Srmanising Stren) Ca ere
ar Os er
feat ae
Gage
ea
ia a Ta
Tye pay
re
2G = RELY AmmaaeN
map
a
1G Lae Dare Sr) ey
°
w
pt!
|
|S)
Ch
< aoa
acs
> Re re ad
may
“hex = DS = 200 - esis a
= ara) K
cia Ear Ne are
e
ci ee an a
- a he Wy feeyers
3 Vl.
One qo Cr
yarns 5
DISCS
caer
OR) = pa
en el (ee R iz
cS = \20 KT) m2 ion wie?
G Ce tao 2)
CWS ogee = 1G
©) Aven = KAU = oo. Sauk
aS Sy oi Sey
Pann DS OC)
{LO6a-V KT
PO ann Ana i
® (ear eae oe ok
os =
a Dy
VTS a ea ae arn a 7%
Es 2-394 wt
® SS eC ahs
Cy
IY SSC foe
LC STOn oy (KO
EOS
Oe aC
rae) a
C= gobo) Ksi
@s
De eae Le
oe ? LEY Loy
wae a Obes Gag
SUBJECT: CREEP, FATIGUE AND FRACTURE [MM 1703]
Missing datayf any, my be assume aly u iy
Pe 1 geal
1] (97) A sample of borosilicate glass contains two cracks: a surface crack oft ,
Vim deep and an inner erack of 1.8,im long. Both the cracks are normal Yn = 0-4
| | to the tensile axis. Determine which one will propagate first on
for molybdenum is given by. |
| rate of (1) 10s.‘ and (ii) 10"s §. E= 350 GN m ?and specific surface
energy p29 m2 pial
z © Creep (steady-state) rate data are given in the table fornickelat | 5
| soe a ae
| al awa) |
| 10: (age aaa)
10:6 rst)
Activation energy for ereep 15 272/000 W/o. Compute the steady
_|_ pa state creep rate ata temperature of 850°C and a stress level of 25 Mi
[@ A cvinarica component constructed from an cree resisting aloy has 3/3
for it to survive 500 h at 925°C. The stress corresponding to 500 h is |
esse era ta hte agi to
Faecal ae Nour Nb ei ne
| parameters: Yield Strength (a>2)= S1OMPa, (ciys)= 90MPa The crack
UH | length was a = 25mm. The geometry factor determined can be
| estimated by equation given below -
az ut | Re f i Pal ayl Al
Egor] | te arsenate amfah sana) sof
ie 1 el
% meee | | praw a plot of the force versus the displacement of the specimen and
| determine fracture toughness of material (Ki).
o {bp [A center-cracked plate has dimensions b = 50 mim, thickness (t)
© | frm, and large fa force of P = 50 KN is applied.
| Cay Wihat is the stress Intensity factor K fora crack length of 2
ERS
=
es a a + (afa)
64 wy
are Bua TA a8 a
Comment Highight Draw Text FIL&SIEN Moretools J
¥ fdiate the right hand margin
that you have go the corret question
‘A. weight of 4 kgf, released from a height of 20 cm In a Charpy Impact test. 3
The height at the end of swing Is 3cm. What is the impact energy? Based on
Impact energy the material ductile ts or brittle
4) Is there any relationship between a material's processing technique and its 2
mechanical properties? Give at least three examples to support your answer:
) Select between Nickel and copper for preparing spring i there resilience value is 2
given
1) Ammaterial of § mm thickness and 20 mm width is deformed and final thickness 3
Of the material Is 4 mm and same wicth, Estimate the desired mechanical
properties.
Fesetenee cc SSeS ET ara
I) the fracture strength of @ material fs 1,112 MPa. what should be the design 2
{ress for the component fora tensile toad of HN. Safety factors 1.5
4) A plate of semi finite width contains embedded circular crack of size 1.9.cm.A 3 ‘
stress of 900 MPa ts applied. The direction of application ofthe stress Is
perpendicular to the major axis. Estimate stress intensity factor. Geometrical
ection factor may be taken as 2/t.
fn infinitely wide plate of stee! has central crack. Comment on whether design 2
{S safe or nt? (Crack size = 2.4 mm long, Fracture Toughness of the materia is
30 MPam! and design stress ic $00 MPa. ty,
1) What isthe critical erack length in iron accondhmto the Griffith Orowan eq 3
= 10" jm?
” 5
(a) Determine the stress required to
‘produce rupture in 2000h at 870°C.
(b) Determine the rupture time at 7600C
for the same stress
’ 5
9
Using the data in the table Calculate the value of Q
ey eget
, 4 808
Comment Highlight Draw Text Fill & Sign More tools
< O
#
scanned with OKEN Scanner Why jolning,
conventional welding
ty very difficult with th
‘metus! suitable for jowning, of
Calelate them iy for 0 phe alloy composed of 50 yvolunw 4
Iity-OF stress hyp
7 GPa, Ey = 690 Gi
smut of 472 €
4 values with the
NRXRARODOOIROORORIOOOOONK TH FNM 20K IR RD
scanned with OKEN Scanner
id EE ‘OF borosiljeate giass ns two Efecks: a Surface crack of 1 | |
|} 8M deep and an inner crack of 1.8 wm long. Both the cracks are normal |
to the tensile axis. Determine which one will propagate first on |
increasingithe appliec load and at what stress? |
Young's Modulug = 65 GN m 7;7=0.5 Im
for molybdenum \s given by
1 y= 20.6 + 173 600/T + 61.3 log,. (de'dt)
| where Tis the temperature in kelvin and (d:/dt) is the strain rate %
s"*, Sharp cracks of length 41m are present in the metal. Estimate the
| temperature at which the ductile to brittle transition occurs at a strain
} rate of (i) 10°75"' and (ji) 10%s"*. E= 350 GN m™ and specific surface
eneray is 2m".
(2) | Creep (steady-state) rate data are given in the table for nickel at 5
998°C
o (MPa)
Activation energy for creep is 272,000 J/mol. Compute the steady-
+ State creep rate at a temperature of 850°C and a stress level of 25 MPa) |
(b) | A cylindrical component constructed from an creep resisting alloy hasa 3
Giameter of 12 mm. Determine the maximum load that may be applied
for it to survive 500 h at 925°C. The stress corresponding to 500 h is
| about 50 MPa.
{ () | Explain two creep mechanisms briefly.
2
3 | (a) | The dimensions of the
specimen according to standard ASTM E-399 are | 7
Total length (L) = 62.5mm, Width (W) = 50mm, Height (H) = €Omm,
Thickness (B) = 25mm. Material has the following material
parameters: Yield Strength (co 2)= 510MPa, (Gm, )= S90MPa. The crack
length introduced by fatigue loading was measured after the test. Its
|
Jength was a = 25mm. The geometry factor determined can be lest
estimated by equation given below |
ies
a 4
Wy - 54h | |
(ap
d ie
Draw a plot of the force versus the displacement of the specimen and }
determine fracture toughness of material (Ki-),
| (b) | A center-cracked plate has dimensions 6 = 50 mm, thickness ()= 5.797
mm, and large h; a force of P = 50 KN is applied.
(2) What is the stress intensity factor K for a crack length of a = 10
mm?
B66 ~ 4.645 13.32]
/
——— SS HE END
|
ae ee es Se
nd
i Given data
Yield strength, , = 480 MPa
Hoop stress, o;, =140 MPa
Tensile stress, c, =80 MPa
Fracture toughness, Kj, = 1400 MPaymm
Y=11
Consider the equation for maximum pressure, at which vessel will burst.
2 (ee
Paw S —
= ae
a)
s - 2 (E
Here, r is radius of pressure vessel. }4G= Paa1 = Py | Moap —|—
a4 YRAG
Consider the equation for hoop stress
a= 2s"
t
2, = 2 ~~
-
Here, ¢, is critical thickness of pressure vessel
Substitute the values of equation (2) in (1) and calculate the thickness of pressure vessel
ee ee anwd- Veo !e0
Z “(| 14 io
1400" “ i
4
2 P \d
M0x6, = x I ging a Grete
£=48.20mm
om
Hence, thickness of pressure vessel is, [48 20mm 2p (wr ae
TMB oy
Y Xd lu x 360x YO
RUG
yo
5
1OS was PIO Aa es CCU SS COLI
EN TVEC COS
rey Elena Cv
a ROE SO EO Pr ets
is ak arth BR rachis %
RUC Naat KC nS
Ao earcsaeed Contos
ieee)
5
Sama Ne La
SCE cn wn)
eg
Pete Et
anaes
fis vee
OC ECS MOT to a
= Aiud of cutuvoture.
one = 9 .
iS Qa A en ree
ome on
oma »
PAs qe
o, ae 22) = Le, |
ald i a iG
[open ea
rar
= Ca MR AOS Se Tac RO
RAC Cre Ce RCSL LC oe
Amery
a
ir
a CNet OG
® Prvinnotetly ube te Gueatet betttle [© Petonaky uked to pYediet Dudily
cE TT SS Tosn rg
Q (eT ivy
@ Me Stacks wack & crack will propoge (Seer e wore 3 ee Pe
VoSrn CTS aa CS CD pillar Comcentreabiony ooun
STUER CO Cras COR ,
OSS ae
ad CW COCR MCLE}
even Soe
wis VMS CSL ad
a ae Pare ry
Kear
Tenn
eNOS ie rh Ysa
Cen CZ
= Sey = Put nr,
= Obie Pare ee eT
Ta Daan
Nt Wok -before - break, condittew
NRT To a OOS 3 ca 3)
p= Ce Paes eecme
Coen cs re
a) Cri ae
on CLs va
Tee No Nate 2-4)
LE Rexsy an acre
226
Yoo he Ce aD)
1p ene See
c= how es es
\ eC ed
[oo rean (CLS
(Ce CC
rns GoomPa,
on mnaag ROE
Kie =
= DBO fs WbeOWi te® ,,
rarer Jes U5.)
Se Le SL aN od
CS yar eee (LO Ce
ale)
yas ae r ae
(OSE
Cb ae oe eae is
rs
Gy, 25 x 2-04
CD a a ad
COTO Nea CEO
SS eo rece
CSOs Design Strength
Expected highest
service load
. vy
os
i a Ce Ed
a ae
Be 5
( ° a PS Qe Plan gerets
a
EE _—- os CTS
xo)
Peon ets Cen as)
(ety
ae RCCL
(ores mr
cerry
a NES
Goon = ae =) i > SCS CRO OCS CORE CRC ROCA Tis ORCUTT
Rene Ca
e
——— Cran
ee!
ry =
cya
Ne yeaa Roe
aa
o oe {= In) E Pays aD]
one ae ah oa cos (12) an
5
1G It CC)
ee
eee Ie
ery & 3h
= A
Rie
an
. LAYS eS (Sram cnt
eae ia Coe Gs y
Ss coer ae
pine e\.
= Ge)
eS et ee ae %)
ee as
ae ‘ i. ea
einai a eemeey
Sree
a a
Lara o a. ( 2 j es ;
na, *e) on Coy & =
Sek IS
3 & = “2S -9 , VS
a ie ain ad
iACreemSSTS Uy Ros Come
Ss eee eee
ond ae
Rn oe coe 4
iy Liss
E'=@ (Plas eves)
acu Carrere
02 3)
ee
%
w= § (way — a)
P
Brora
Cs OO Ck eal
A id fan
ea
ea)
Ce SS ae