THE MINIMUM J₂ CRITERION FOR I-Ⅱ MIXED MODE BRITTLE FRACTURE

In practical engineering, mixed-mode fractures of material are commonplace. So the analysis of mixed-mode crack is of both theoretical importance and practical value. J₂, the second invariant of stress deviator tensor, is considered here to predict the I-Ⅱ mode crack initiation angle and critical load. The results are in good agreement with experimental data, which confirms the fact that the distortion energy plays a major role during the strain energy transformation caused by crack initiation. It is also found that the non-singular term in the series expansion of the stress parallel to the crack around the crack tip, has an effect on the crack initiation angle and the critical load.