Systematic Builder for All-Atom Simulations of Plastically Bonded Explosives

TL;DR

This paper introduces PBXGen, a versatile method for constructing realistic all-atom microstructures of plastically bonded explosives, enabling detailed simulations of hotspot formation and energy localization.

Contribution

The paper presents PBXGen, a novel approach to generate realistic PBX microstructures for atomistic simulations, extending beyond idealized defect models.

Findings

Microstructures validated against experimental mechanical properties

Demonstrated applicability on RDX-polystyrene and TATB-polystyrene systems

Structures capture key features of PBXs at smaller scales

Abstract

The shock to detonation transition in heterogeneous plastically bonded explosives is dominated by energy localization into hotspots that arise from the interaction of the shockwave with microstructural features and defects. The complex polycrystalline structure of these materials leads to a network of hotspot that can coalesce into deflagration and detonation waves. Significant progress has been made on the formation and potency of hotspots using atomistic simulations, but most of the work has focused on ideal and isolated defects. Hence, developed a method, denoted PBXGen, to build realistic PBX microstructures for all-atom simulations. PBXGen is generally applicable, and we demonstrate it with two systems: an RDX-polystyrene PBX with a 3D microstructure and a TATB-polystyrene with columnar grains. The resulting structure exhibit key features of PBXs, albeit at smaller scales, and are validated against experimental mechanical and shock properties.