Issue 14

C.M

. Sharanaprabh

u et alii, Frattu

ra ed Integrità S

trutturale, 14 (2

010) 27-35; DO

I: 10.3221/IGF-E

SIS.14.03

app Mo be CT Th plo res of pro equ is 0 ind

lied load 4k de-II loading used as inpu S specimen. e variation o t of MPZR pectively. It i loading angle portional to ation to all t .0066 for an ependent of

N. These res only. The re ts for minim f the minimu vs. K eff for v s interesting s. These figu the effective he MPZR da alytical resul loading angle 0.0066 m M  0.0068 m M  d 16 show th

ults clearly d sults of MPZ um plastic zo m plastic zo arious loadin to note from res infer tha stress intens ta. Such a lin ts and 0.0068 can be expr 1 2 m Pa 1 2 m Pa at there is an

emonstrate R estimated ne radius (M ne radius (M g angles est these figure t for any load ity factor. Th ear fit is show for FEA re essed as follo

that the spec using the th PZR) criteri PZR) vs. eff imated by an s that the var ing angle (fo e proportion n in Fig.15a sults. From ws:

imen experie eoretical and on for crack ective stress alytical and iation of of M r the analytic ality constan and Fig.15b these results,

nces minimu the finite ele initiation [4] intensity fact FEA are dep PZR vs. K al and the F t can be eval . The slope the relation

m plastic zo ment in this in mixed mo or (K eff ) is al icted in Fig eff is linear an EA), the gro uated by fitti of the estima between the

ne radius un investigation de loading f so studied. .15a and Fig. d is independ wth of MPZ ng a straight ted linear fit MPZR and

der can or a The 15b ent R is line line K eff

eff MPZR K

(Analytical)

(15)

eff MPZR K e Eqns. 15 an

(FEA)

(16)

Th

insignifican

t difference i

EA and ana

lytical metho

n the results

obtained by F

ds.

 (a) analytica imen indepen MPZR crite udied with re ding angle o in Fig.16. T lts shown in imilar. A sm ibly be attrib ack in mixed itude of  o n in Fig. 16 ed for plane nt, and for a a validation

Figure d 16 can be he proposed tion the angl e finite elem the similar 82.5° to 0° a arious applie mpared with jig. Bian an specimen. T riation of  o m [4], as th Mode-I loa perpendicula

15 : Variation o used to estim Eqns. 15 and e at which M ent analysis. results by Bia s  changes d loads and the FEA  d Kim [4] ha hese investig vs .  obtained e theoretical ding crack i r to the ligam

f MPZR vs. K ate MPZR in 16 can be o PZR occurs The variation n and Kim [ from 0° to 9 a particular o for various ve considere ators have u in present a results in [4 nitiates along ent. In this

eff for various a CTS spec f great use in (  o ) is also st of  o vs . loa 4] is depicted 0°. The resu  is almost s  can poss d that the cr sed the magn nalysis show ] are obtain the ligame investigation

l and (b) FEA dent of the l ria. spect to the btained in th his figure sh Fig. 16 indic all dissimilar uted to varie mode loadin for defining t slightly diffe strain analy specimen u of minimum

results. oading angle loading angle is analysis fo ows that the ate that the ity observed d loading co g initiates in he crack init rs from the t sis. Fig. 16 s nder mode- plastic zone

Th or v In ana loa dec com ana thr MP nat of

e Eqns. 15 an ice versa. T this investiga lytical and th ds along with reases from puted for v lytical  o co ough loading ZR in a CTS ure of the va Bian and Ki cimen under iates almost

if K eff

is kno

wn,

(  ) both for r various app magnitude o magnitude o in the estim ndition in F the direction iation angle. heoretical res hows that fo II loading c radius (MP

the lied f  o f  o ated EA of The ults r a rack ZR)

spe init

34