Investigation of fracture trajectory in blunt V-notched specimens under mixed mode I-II loading

In this paper, the fracture trajectory in blunt V-notched specimens under mixed mode loading is investigated by using two numerical approaches: 1) the extended finite element method (XFEM), 2) the incremental method. The first approach is an extended form of the finite element method in which the fracture takes place and grows according to the cohesive zone model. The second one is also an increment approach which the fracture initiation angle for notched specimen is first determined according to the concept of the maximum tangential stress (MTS) criterion. Afterward, a small crack is added to the notched specimen along the fracture direction and then a new cracked specimen is generated. In the next step, the fracture initiation angle is calculated from MTS criterion and another small crack is again added to the cracked specimen. These steps are continued until the crack reaches to the back boundary. To evaluate these methods, the fracture paths of the rounded-tip V-notched Brazilian disk (RV-BD)specimens under mixed mode loading are predicted by both XFEM and incremental method. It is shown that the incremental method can provide estimates more accurate than XFEM for the fracture initiation angle of the notched samples. It is also demonstrated that both methods can predict the fracture trajectory in good agreements with the experimental results