A review of mixed mode I-II fracture criteria and their applications in brittle or quasi-brittle fracture analysis

Fracture criteria play a very important role in predicting crack propagation behavior and life evaluation of cracked bodies. In this paper, mixed mode I-II fracture criteria in the framework of linear elastic fracture me-chanics and their applications in brittle or quasi-brittle fracture analysis are systematically reviewed. Meanwhile, the advantages and shortcomings of these criteria are briefly discussed. Furthermore, the effects of T-stresses on brittle fracture characteristics are also studied and some suggestions are given to select appropriate fracture criteria. The results show that different types of fracture criteria differ greatly in predicting the crack propagation behavior, and a suitable criterion can be chosen according to the crack types, loading modes and failure char-acteristics. Tension-based fracture criteria are applicable for the opening cracks under tensile-based failure, but not for the closed cracks under shear-based failure. T-stresses around the crack tip have significant effects on crack initiation angle, fracture resistance and crack tip plastic zone, which should be introduced into the classical fracture criteria only determined by singular terms for providing more accurate predictions. Moreover, the variable fracture process zone radius can be further considered in these modified criteria considering stress in-tensity factors and T-stresses, which are not only suitable for brittle materials, but also for plastic materials under small scale yielding. This review will contribute to the development of mixed mode fracture criteria.

Automated summary

In this paper, the application of mixed mode I-II fracture criteria within the framework of linear elastic fracture mechanics is systematically reviewed. The effects of T-stresses on brittle fracture characteristics are studied and recommendations for selecting appropriate fracture criteria are given. The review concludes that different types of fracture criteria differ greatly in predicting crack propagation behavior and that the consideration of T-stresses and variable fracture process zone radius can improve the accuracy of predictions. This review will contribute to the development of mixed mode fracture criteria.