ELASTO-PLASTIC CRACK GROWTH SIMULATION USING XFEM

Abstract

The simulation of any physical problem by the finite element method or by other domain type methods can be very complex. The modeling of complicated domain is difficult using standard finite element method since the mesh should confirm the boundaries of domain or discontinuities. The extended finite element method (XFEM) can capture the discontinuities present in the domain though enrichment without changing the mesh size. In this report, the fatigue crack growth and creep crack growth modeling is carried out in conjunction with the XFEM. The nonlinear material behavior is modeled by a class of power law hardening. The Von-Mises yield criterion with isotropic hardening is assumed in the analysis. The analysis of crack tip stress field and displacement field is carried out assuming plane stress condition. The calculation of stress intensity factors for respective mode is done by decomposition off-integral method and the basis of fracture criterion for crack growth based on critical stress intensity factor is studied theoretically. The fatigue crack growth rate and fatigue life are validated with the experimental results for the compact tension (CT) specimen. Furthermore, creep crack growth is also modeled and results are compared with available literatures. The creep law" has been used to model creep of the material. This report provides detailed review of past development of fatigue and creep crack growth analysis and description of XFEM. In last part of this report adaptive mesh refinement has been discussed and convergence study of hanging node with and without degree of freedom is shown.