Molecular Dynamics Simulation of Pore Collapse Due to Converging Shock Waves in RDX

The shock sensitivity of many heterogeneous energetic materials is related to the mechanical and thermal characteristics of hot spots formed due to the collapse of nanoscale porosity. This shock-induced collapse has been studied extensively in many energetic materials using all-atom non-equilibrium molecular dynamics (MD), but studies have been limited to the interaction of a planar shock wave with such features. The effect of curved and focusing shocks are not well understood and are the focus of this work. We used large-scale MD to study void collapse caused by a cylindrically converging shock wave in RDX. Here we explore how shock strength affects dissipation mechanisms, pore collapse mechanism, and the collapse temperature, for a focusing shock. Methods for modifying energy localization via selectively removing parts of the converging shock are also discussed.