Title: Hotspot Formation in Shock-Induced Void Collapse of Pentaerythritol Tetranitrate (PETN)
Presenter: Ray Shan
Affiliation: Sandia National Laboratories
Abstract: We present results of molecular dynamics simulations of hotspot formation in shock-induced void collapse of pentaerythritol tetranitrate (PETN) with the ReaxFF reactive force field. Chemical species analysis is performed with a recently implemented on-the-fly analysis capability. A supported shockwave is driven through a PETN crystal; void size and piston velocity are varied to investigate their effects on hotspot formation and detonation initiation. Formation of hotspots during void collapse is characterized by hotspot extent and maximum temperature. Results show hotspot extent is directly related to void size, but maximum temperature is only slightly affected. On the other hand, both hotspot extent and maximum temperature are strongly dependent upon piston velocity. We observe enhanced initiation sensitivity due to larger voids. During void collapse, NOX molecules are shown to be the dominant ejectile from the upstream void surface. Once the void is filled and the hotspot develops, formation of final products such as N2 and H2O become more dominant.