A mechanistic model for shock initiation of solid explosives

TLDR

The study develops a model for ignition and detonation growth in pressed solid explosives, examining how microscopic topology influences shock initiation. The model couples microscopic viscoplastic pore collapse and pore/ grain combustion with a macroscopic shock‑tracking framework that captures wave propagation and scale couplings, incorporating pore and grain size distributions. Validation against pressure gauge data and Pop‑plots confirms the model’s accuracy.

Abstract

This paper is devoted to the building of a model for the ignition and growth of a detonation in pressed solid explosives. The ignition model describes the various phenomena occurring at the microscopic scale during viscoplastic pore collapse. The growth stage is represented by a model combining inner combustion inside the pores and outer combustion on the surface of the grains. These microscopic models are incorporated into a macroscopic one. The macroscopic model reproduces waves propagation and takes into account the various couplings between the microscopic and macroscopic scales. Pores and grain size distributions are also considered. The governing equations are solved using a shock tracking high resolution scheme, in order to avoid numerical smearing of the shock front. The role of microscopic topology of the explosive is investigated. Results are validated on pressure gauge records and shock to detonation transition distance (Pop-plots).