T-stress of an interface macrocrack induced by near tip subinterface microcracks

Determination of the T-stress of an interface macrocrack induced by near tip subinterface microcracks is performed. Based on the general solution of the macro-microcrack interaction, the induced T-stress can be evaluated by using the principle of superposition. Numerical examples of an interface macrocrack interacting with a single near tip subinterface microcrack are considered and the results are shown graphically. The induced T-stress is shown to be significantly dependent on the location and orientation of the near tip microcrack. The induced T-stresses of the upper crack face (Delta T+) and the lower crack face (Delta T-) are different. The difference disappears only when the microcrack is located and oriented definitely, for which both Delta T+ and Delta T- become zero. Delta T+ and Delta T- have the same sign, i.e., simultaneously positive or negative. The positive or negative value is dependent on the location and orientation of the microcrack.