Issue 14

ana res FE com Th (  ) res Th dep iso con Th pur ana  = pla are Fig lytical formu pectively. Th analysis thr puted using eff K  Figure 5 : Vari 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. ure 7 : The seq analyti lation and pr is discrepanc ough loadin the relatio n 2 2 I II K K  ation of K II vs 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 uential develo cal Eq. (10) fo C.M. Sh esent FE res y in estimate g Jig. The e [9]: . K I for differe 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 pment of plas r various loadi aranaprabhu et ults. It is fou d magnitude ffective stre nt applied loa 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 tic zone obtain ng angles. alii, Frattura ed nd that ther s of stress in ss intensity ds. F 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 ed by Fig ap Integrità Strutt e is 10.5% an tensity facto factors (K eff ) igure 6 : Variat 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 ure 8 : Sequen plied loads. N ap urale, 14 (2010) d 2.4% erro r attributed t under mixe ion of K eff vs .  analyses are ) i s 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 tial developme umber 1,2,3,4 plied load 4, 6 27-35; DOI : 10 r in estimatio o varied load d mode loa for different 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 nt of plastic z indicates the p , 8 and 10 kN .3221/IGF-ESIS. n of K I and ing conditio ding have b (14) applied loads. 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 one for variou lastic zone fo . 14.03 31 K II n in een ngle rlier e is ting stic ape. the e of gles the g. 8 s r