Investigating the effect of T-stress on brittle fracture of PMMA under mixed mode conditions

Many experimental and numerical investigations have been performed in mixed mode loading condition to investigate the behavior of linear elastic material in brittle fracture. One of the best materials for this purpose is polymethylmethacrylate (PMMA) which has been used mostly by researchers. As a result of these efforts, many proposed fracture theories have been evaluated on various kinds of specimens of PMMA. In most previous studies, the two common criteria in fracture mechanics, the conventional maximum tangential stress (MTS) and generalized maximum tangential stress (GMTS) criteria were utilized. The above criteria are related to the basic terms of the fracture mechanics called stress intensity factors, KI and KII, which show the severity of the stress around the crack tip. The difference between MTS and GMTS criteria is associated with the other item known as T-stress, the stress parallel to the crack. The main idea of this paper is to compute the values of T-stress in three-dimensional finite element models to explain the available experimental on PMMA and numerical results.