Numerical investigation of mixed-mode crack growth in ductile material using elastic-plastic XFEM

In the present work, the corrected extended finite element method (XFEM) is extended to conduct fatigue analysis of arbitrary crack growth in ductile materials. In corrected XFEM, the crack is modeled by adding enrichment functions into the approximation; optimal convergence rate and independent mesh discretization can be achieved, and the re-meshing and refinement during crack evolving can be avoided. von Mises yield criterion along with isotropic hardening is used to model finite strain plasticity. The nonlinear problem is solved by Newton-Raphson iterative method. Interaction integral method is employed to calculate mixed-mode stress intensity factors. Crack growth angle and rate are determined by the maximum principal stress criterion and the modified Paris law, respectively. Two problems, i.e., ductile crack growth in round compact tension specimen and ductile crack growth in overhanging beam are presented. The numerical results are compared with experimental data as well as FE simulation, to demonstrate the excellent capability of XFEM for simulating arbitrary crack growth in ductile materials.