Issue 14

C.M. Sh esent FE res y in estimate g Jig. The e [9]:

aranaprabhu et ults. It is fou d magnitude ffective stre

alii, Frattura ed nd that ther s of stress in ss intensity

Integrità Strutt e is 10.5% an tensity facto factors (K eff )

urale, 14 (2010) d 2.4% erro r attributed t under mixe

27-35; DOI: 10 r in estimatio o varied load d mode loa

.3221/IGF-ESIS.

14.03

ana res FE com

lytical formu pectively. Th analysis thr puted using

lation and pr is discrepanc ough loadin the relation

n of K I and ing conditio ding have b

K II n in een

2 K K 

2

eff K 

(14)

I

II

vs

Figure 5 : Vari

ation of K II

. K I

for differe

nt applied loa

ds.

vs . 

ion of K eff

F

igure 6 : Variat

for different

applied loads.

f K eff estimat in Fig.6. Th ained by the The shape o stress, which r the materia tual plastic zo y the consid lopment of I) is shown i d in each loa

Th (  ) res Th dep iso con Th pur ana  = pla are

e computed m for various a ults [9, 13]. e plastic zon endent on lo -contours of stitutive mo is is different poses of the lysis. The se 36 o (Mixed m stic zone con set to zero.

agnitudes o pplied loads e shapes obt ading angle. the effective del is used fo from the ac present stud quential deve ode-I and I tour obtaine

ed by analyti e nature of v Eq. 10 is sh f the plastic causes yield l, contour plo ne that is af eration is fo crack-tip pla n Fig. 8. The d step. For s

cal and the f ariation of K own in Fig.7 zone ahead o ing according tting of the fected by str cused on th stic zone for plastic zone implicity the

inite element eff vs .  (Fig.6 . This figure f a crack-tip to von Mis von Mises str ess redistribu e plastic zon various app contours in displacemen

analyses are ) is in good indicates tha by FEA has es criterion [1 ess correspo tion during p e, due to the lied loads an Fig. 8 are ob t scaling of th

plotted again agreement w t the shape o been ascerta 4]. Since, in nds to the pl lastic flow. H considerabl d typically fo tained by su e specimens

st loading a ith similar ea f plastic zon ined by plot this study ela astic zone sh owever, for y greater eas r loading an perimposing shown in Fi

ngle rlier e is ting stic ape. the e of gles the g. 8

Fig

ure 7 : The seq analyti

uential develo cal Eq. (10) fo

pment of plas r various loadi

tic zone obtain ng angles.

ed by

Fig ap

ure 8 : Sequen plied loads. N ap

tial developme umber 1,2,3,4 plied load 4, 6

nt of plastic z indicates the p , 8 and 10 kN

one for variou lastic zone fo .

s

r

31