Modeling of crack growth in ductile solids

In this study, two types of approaches are considered to model material failure process and crack propagation in ductile solids. In the first approach, voids are considered explicitly and modeled using refined finite elements. A distinct advantage of this approach is the exact implementation of the void growth behavior. In order to establish crack advance, a failure criterion for the ligament between a void and the crack tip is required, which can be obtained by conducting systematic finite element analyses of the void-containing, representative material volume subjected to different macroscopic stress states. In the second approach, voids are considered implicitly by using porous plasticity models. This approach is attractive for simulation of extensive crack growth because detailed modeling of each individual void is avoided. As an example, a numerical approach is proposed to predict ductile crack growth in thin panels of a 2024-T3 aluminum alloy, where a porous plasticity model is used to describe the void growth process and the material failure criterion is calibrated using experimental data. The calibrated computational model is applied to predict crack extension in fracture specimens having various initial crack configurations. The numerical predictions agree very well with experimental measurements.