Issue 48

R. Nikhil et alii, Frattura ed Integrità Strutturale, 48 (2019) 523-529; DOI: 10.3221/IGF-ESIS.48.50 528 For a given strength mismatch level, the η values have been found to decrease as the weld width is increased from 4 mm to 16 mm. This result is in agreement with literature [9,10]. Further the η values have been found to decrease with strength mismatch except between M =2 & 2.2 where they are quite insensitive to mismatch. The similar trend has been reported in literature [10]. The η values vary with configurations, however the mean η value follow a trend line for M =1.6, 1.8, 2.0 and 2.2. The mean η value for M =1.2 is nearly constant for various h /W ratios, for M =1.4 it varies between 2.185 to 1.927. It is also observed that η decreases monotonically with increasing M, except for intermediate weld width i.e. h/ W = 0.16 and 0.24 as shown in Fig. 8. For C(T)configurations with M =1.6 to 2.2, there is a similarity and decreasing trend as the h /W ratio increases. The maximum mean η value is 2.16 and the minimum of 1.68. Figure 8 : η vs M for b /W=0.45. C ONCLUSION he following important conclusions are drawn based on present study. 1. A validated finite element analysis yield contour (FYC) approach based on elastic-plastic material model is used to estimate limit load. 2. The plastic η factors for various configurations of C(T) specimen with weldment parallel to crack plane has been proposed to evaluate plastic J -integral. 3. For smaller strength mismatch ratio, M ≤1.4 the variation of mean η value is 2.2 to 1.93 hence evaluating configuration specific plastic η factor may not influence severe on J -estimation. 4. For larger values of M >1.4 the plastic η factor vary from 2.16 to 1.68, hence the values are C(T) configuration specific. R EFERENCES [1] Clarke, G.A. and Landes, J.D. (1979). Evaluation of the J Integral for the Compact Specimen, Journal of Testing and Evaluation, JTEVA, 7(5) , pp. 264–269. DOI:10.1520/JTE10222J. [2] Wang, Y.Y., Reemsnyder, H.S. and Kirk, M.T. (1997). Inference equations for fracture toughness testing: numerical analysis and experimental verification, ASTM Special Technical Publication (1321), pp. 469–484. DOI: 10.1520/STP12325S . [3] Smith, E. (1992). The use of eta factors to describe the J integral: the ASTM 1152 standard for the compact tension specimen, Engineering Fracture Mechanics, 41(2), pp. 241-246. DOI: 10.1016/0013-7944(92)90184-G. [4] Panontin, T.L., Makino, A. and Williams, J.F. (2000). Crack tip opening displacement estimation formulae for C(T) specimens, Engineering Fracture Mechanics, 67, pp. 293-301. DOI: 10.1016/S0013-7944(00)00048-5. [5] Cassanelli, A.N., Cocco, R. and de Vedia, L.A. (2003). Separability property and ɳ pl factor in ASTM A387-Gr22 steel plate, Engineering Fracture Mechanics, 70(9), pp. 1131-1142. DOI: 10.1016/S0013-7944(02)00095-4. [6] Kim, Y.J., Kim, J.S. and Cho, S.M. (2004). 3-Dconstraint effects on J testing and crack tip constraint in M(T), SE(B), SE(T) and C(T) specimens: numerical study, Engineering Fracture Mechanics, 71(9–10), pp. 1203–1218. DOI: 10.1016/S0013-7944(03)00211-X. T