A generalized maximum energy release rate criterion for mixed mode fracture analysis of brittle and quasi-brittle materials

A modified mixed mode fracture criterion, called generalized maximum energy release rate criterion, is proposed to predict the fracture initiation angles and estimate the fracture resistances in brittle and quasi-brittle materials under mixed mode loading. With this generalized maximum energy release rate criterion, the energy release rate around the crack tip is calculated by considering the contributions from both singular stress terms and T-stress. Experimental data, extracted from prior literatures for central cracked Brazilian disk, cracked semi-circular bend and edge-crack triangular specimens, are used to validate the modified criterion and evaluate the accuracy of the prediction obtained from this modified criterion. Results show that the T-stress plays a remarkable role in the mixed mode I/II fracture analysis when the energy-based criterion is employed. In addition, it is shown that the modified criterion can well predict the mixed mode I/II fracture behaviors of brittle and quasi-brittle materials.