Extension of Tsai-Hill failure concept for mixed-mode I/II fracture investigation of orthotropic materials considering T-stress effects

An essential study in the discourse surrounding composite materials is the investigation of their fracture mechanics due to the intricate nature of composite structures, it is necessary to take into account the presence of cracks and faults throughout the design process. In this research, within the context of linear elastic fracture mechanics, the fracture criterion for orthotropic materials under mixed mode II/I loading is presented by expanding the Tsai-Hill failure criterion. According to the crack, it may be aligned or perpendicular to the fibers; the criterion is stated for both cases. Also, the effects of the non-singular stress component on crack growth have been investigated. The mechanical and fracture data of Russian pine wood was extracted through tensile testing and the finite element (FE) method. The validity of the proposed criterion, in comparison with the experimental findings extracted in this research, has been proved. The precision of the previous proposed fracture criteria has been reviewed in comparison with the proposed criterion. The appropriate behavior of the fracture limit curves compared to the experimental data shows the efficacy of the proposed criterion to predict the initiation and propagation of cracks in orthotropic materials.