Numerical simulation of material fragmentation with material point method

Abstract

The material point method (MPM) is extended to the simulations of material fragmentation due to detonation. A crack modeling scheme based on contact algorithm with material failure process is developed to study the dynamic crack propagation in plastic media. Particles after failure are transformed to a different velocity field by contact method, which makes the crack surface not constrained by grid lines and free to propagate dynamically in any direction even when the material experiences large plastic strain increments. The random characterization of the fragmentation can be described by both microscopic defect and macroscopic failure. When considering microscopic damage of material, the plastic behavior is described by Gurson model with randomly-distributed initial void of material points. Gurson model can degenerate to J2 plastic theory while the microscopic void is ignored, in which situation the Weibull random failure scheme will be used. Meanwhile, an efficient background-grid-based searching method is proposed to capture the statistical feature of the fragmentation.