Issue 47

S. Akbari et alii, Frattura ed Integrità Strutturale, 47 (2019) 39-53; DOI: 10.3221/IGF-ESIS.47.04 46 k i j l 1 2 3 0 1 1 0.374 - 0.376 0 2 0.739 2.314 0 3 0 0 0 2 1 - 0.036 0.1395 0 2 0.075 - 0.594 0.077 3 0 - 1.685 0 3 1 0 0 0 2 0 0.217 - 0.324 3 0 0.2104 1.199 1 1 1 0.292 - 0.034 0 2 0.662 1.444 0 3 0 0 0 2 1 - 0.044 0.072 0 2 0.097 - 0.784 - 0.144 3 0 - 1.043 0 3 1 0 0 0 2 0 0.328 - 0.243 3 0 0.001 1.22 Table 4: Coefficient B kijl in the boundary correction factor for reference loads. A set of computations have been accomplished to identify the accuracy of the derived WF expressions. The stress distribution is applied as an input to calculate the SIFs using the WF integral in Eqn. 3. The SIFs are computed from WF for the quadratic and cubic stress distribution acting on the crack faces using n=2 and 3 in Eqn. 1 respectively. The calculated SIFs were compared with the FEM results, and these comparisons are shown in Tab. 5-7, for R o /R i =1.5, 2.25 and 3.0, respectively. The comparison between the computed and FEA results point out that the derived WF can be applied for reliable calculation of the lug with quarter-elliptical crack. The maximum difference does not exceed more than 7 percent. a/c c/B Location K N =K I /   0 . / a Q   parabolic cubic WF FEM WF FEM 0.2 0.2 surface 0.203 0.210 0.142 0.150 deepest 0.470 0.464 0.436 0.445 0.4 surface 0.197 0.202 0.137 0.144 deepest 0.463 0.448 0.428 0.413 0.6 surface 0.195 0.201 0.137 0.143 deepest 0.457 0.451 0.422 0.417 0.8 surface 0.202 0.212 0.142 0.150 deepest 0.454 0.466 0.420 0.429 1 0.2 surface 0.192 0.187 0.130 0.129 deepest 0.868 0.839 0.766 0.750 0.4 surface 0.240 0.235 0.169 0.166 deepest 0.879 0.846 0.789 0.756 0.6 surface 0.337 0.318 0.245 0.247 deepest 0.969 0.991 0.864 0.841 0.8 surface 0.478 0.497 0.358 0.379 deepest 1.132 1.156 0.997 1.008 Table 5 : Comparison between the SIFs calculated by the WF and FEM for the parabolic and cubic loading at ratio R 0 /R i =1.5.