Effect of the T-Stress in Microcrack Shielding Problems

Abstract

The effect of the T-stress in microcrack shielding problems is studied by solving the interaction problem of a macrocrack with near tip microcracks applying a discrete model. The T-stress has no effect on the results for the parallel microcrack cases; however, it plays an important role for the oriented microcrack cases, especially for large values of the T-stress and large distances of the microcrack center from the macrocrack tip. In determining the shielding or amplification effect of the oriented microcracks, it is necessary to consider the effect of the T-stress. The effect of the T-stress on microcrack shielding or amplification is substantially dependent on the sign and magnitude of the T-stress as well as on the geometry of the microcrack arrangement. The contribution to the J-integral induced from the microcracks is reexamined by considering the T-stress and shown to be still in a consistent relation with those induced from the macrocrack tip and the remote stress field.