Three-dimensional dynamic and quasi-static crack growth by a hybrid XFEM-peridynamics approach

This paper aims at presenting a hybrid computational strategy and its detailed implementation for simulation of crack propagation problems in three-dimensional (3D) solids. The key idea of the hybrid approach lies in the combination of extended finite element method (XFEM) and bond-based peridynamics (PD), which takes excellent features of the high computation efficiency by the XFEM and the flexibility by the PD in dealing with crack growth problems. The PD theory is restricted to the region where crack tips are located and cracks grow, while the XFEM theory is applied in the rest of the specimen. One of the merits of this integrated approach allows cracks to grow naturally without any fracture criteria, and it thus enhances the computation efficiency as compared to the pure PD. It additionally removes most of the problems due to the surface effects typical of nonlocal methods. Explicit integration scheme and implicit solving scheme are used for crack propagation problems under dynamic and quasi-static loading conditions. Numerical examples with 3D dynamic and quasi-static crack propagation cases are considered to show the accuracy and performance of the developed method. Reproducing the shape of the experimentally observed crack is demonstrated. For dynamic crack propagation, we additionally explore the change of the crack propagation speed during the cracking process, and the crack propagation speeds from the present method match well with the reference solutions.