On the consequences of T-stress in elastic brittle fracture

By using a generalized maximum tensile stress (MTS) criterion to predict onset of brittle fracture, it is shown that the presence of T-stress can have a significant effect on mode I and mode II toughness. The most prominent influence of T-stress on toughness occurs for mode II conditions. However, earlier tests concentrated on near mode I and results were masked by scatter. New experiments, using combinations of mode II loading and T-stress, support conclusively the generalized MTS criterion. This criterion is shown to be very robust and applicable to predicting probability of brittle failure. The criterion is also relevant to other experimental results where combinations of mode II loading with high values of T-stress can lead to values of mode II toughness that are greater than mode I toughness.