Mixed-Mode Creep Crack Growth Simulations Using Continuum Damage Mechanics and Virtual Node XFEM

Abstract

In this work, mixed-mode elasto-plastic creep crack growth simulations are performed through virtual node extended finite element method. The continuum damage mechanics is combined with virtual node extended finite element method (VNXFEM) to avoid the requirement of fine mesh. The VNXFEM models the crack growth within an element using coarse mesh. J2 plasticity model is used to model the plasticity of isotropic and homogeneous material. To maintain the equilibrium in the elasto-plastic analysis, Newton–Raphson method is implemented. Creep strains and damage variable are computed from Liu–Murakami creep damage model. To solve the creep and damage equations, forward Euler method is applied. To reduce the local behavior of damage (mesh dependency of damage), mesh regularization schemes are adopted. P91 steel specimen at 650 °C is used and 2-D plane strain condition is assumed for simulating the mixed-mode crack propagation. The present study summarizes that VNXFEM is an effective method to model the crack propagation with a coarse mesh.