Fracture Criterion of a Mixed-Mode Crack (2nd Report, Mode II Fracture Criterion and Criterion for Judging Fracture Mode)

In the first report, it was shown that, as far as the mode I (opening type) fracture occurs, the criterion ([formula omitted] criterion) based on the mode I contribution of ε_φ (crack energy density in an arbitrary direction) is effective from completely elastic fracture to elastic-plastic fracture with large yielding region through the application of [formula omitted] criterion to the fractures of an inclined crack under tensile type loading. However, the mode II (shear type) fracture may occur under some conditions. So, in this paper, the criterion ([formula omitted] criterion) based on the mode II contribution of ε_φ is proposed as the criterion for the mode II fracture first. Subsequently, the fracture experiments of an inclined crack under shear type loading are carried out and, based on the experimental results, its applicability to mode II fractures is shown in addition to the applicability of [formula omitted] criterion to mode I fractures and, moreover, the criterion for judging fracture mode is discussed. Finally, by summarizing the results in this paper and those in the first report, the most generalized mixed-mode fracture criterion which can also judge fracture mode is given.