Open Access Open Access  Restricted Access Subscription Access

Exploring the Physics of Dynamic Fragmentation through High- Performance Computing



Dynamic fragmentation of brittle materials is of great importance in several applications (transportation safety, ballistic impact, asteroid impact, to name a few). The rapid breakage of a body is governed by complex physics. The initiations of microcracks at materials defects, their propagation at high velocities, and the subsequent branching and coalescence, yielding fragments, are all influenced by stress wave interactions. In this presentation, we review past experimental and theoretical work on dynamic fragmentation. We then describe a novel methodology in which the Discontinuous Garlerkin framework coupled to cohesive elements [1] is used to conduct highly scalable simulations of three-dimensional bodies. We conduct massively parallel calculations to generate converged fragmentation results. We show that for fine enough meshes, the average fragment size becomes independent of mesh resolution. Our simulations also reveal the existence of simple scaling laws for the distribution of fragment sizes. Our numerical results agree with some conclusions of the well-establish energy models [2]. For instance, we find a -2/3 exponent dependence of fragment size with strain rate. However, we illustrate the power of scientific computing by obtaining statistics, which are not within reach of analytical work. In particular, we discuss recent dome-explosion calculations, in which fragment shapes are shown to depend on material defects and the extent of crack branching.

Full Text: