Numerical analysis of mixed Mode I and Mode II fracture propagation

Abstract Previous experiments have shown that both Mode I and Mode II fracture propagation can occur when a fracture in brittle material such as rock is subjected to compression. In this paper, the mixed mode fracture propagation has been successfully simulated with a new numerical approach using the Displacement Discontinuity Method (DDM) and a fracture criterion based on G Ic and G IIc . The experimental results of fracture coalescence observed by Reyes and Einstein are simulated using this new approach. Both the coalescing paths and critical loads in the simulation are similar to the experimental results. The new approach has also been used to study the influence of loading conditions and material properties on the propagation mode. Low Mode II fracture toughness and high confining stress are shown to favor Mode II fracture propagation.