In the ability to extend Hashin criterion for mixed mode I/II fracture assessment of cracked orthotropic materials

The problem of fracture assessment of orthotropic materials under mixed mode I/II loading is investigated in this study. The Hashin criterion, which is widely used to study the failure of composite materials, is extended to cracked orthotropic materials. The crack is assumed to grow along the fibers and in the isotropic matrix media. Hashin criterion as a well-known formulation for failure investigation of composites is extended to cracked orthotropic materials with two different approaches. As a first approach, the orthotropic stress field around the crack tip is considered for extraction of the extended Hashin criterion (EHC). In the next one, Hashin criterion is considered in conjunction with the reinforcement isotropic solid (RIS) concept as a superior material model named here as HC-RIS. Accuracy of the results is evaluated by comparing the fracture limit curves extracted from EHC and HC-RIS with the available experimental data which have been extracted from double cantilever beam (DCB) and single edge notched tension (SENT) test specimens on Scots pine, Eastern red spruce and Norway spruce.