FINITE ELEMENT SIMULATION OF MIXED-MODE CRACK PROPAGATION BASED ON STRAIN ENERGY DENSITY CRITERION

Abstract

Prediction of crack growth path is pre-requisite for estimating the fatigue life of structures. A combination of loading, structural geometries and material properties can significantly influence the crack propagation. This paper presents finite element modeling of mixedmode crack propagation in two-dimensional linear elastic problems by adopting the strain energy density (SED) criterion. The main objective is to predict the path of crack growth under mixedmode conditions. According to the SED criterion, the crack path will follow the direction of minimum strain energy density factor. In finite element models, the ring elements are constructed around the crack tip at each crack propagation stage. Strain energy density values in the ring elements are then used to determine the direction of minimum strain energy density factor. Once the direction is known, an increment of crack propagation is assumed, and a new mesh with ring elements is generated for the next crack propagation stage. Examples are illustrated for comparisons with experimental results of two crack configurations, which are a plate with an inclined central crack and the modified compact tension specimen.