Modeling pore collapse and chemical reactions in shock-loaded HMX crystals

18th APS-SCCM; 24th AIRAPT

Austin, R.A.^1 ; Barton, N.R.^1 ; Howard, W.M.^1 ; Fried, L.E.^1

Lawrence Livermore National Laboratory, 7000 East Ave, Livermore

CA

94550, United States^1

关键词: Decomposition reaction;    Energy localization;    Finite element codes;    Localization of deformation;    Reaction initiation;    Stress wave amplitude;    Thermo-elasto-viscoplasticity;    Transformation kinetics;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/500/5/052002/pdf
DOI  :  10.1088/1742-6596/500/5/052002

来源: IOP

【 摘 要 】

The localization of deformation in shock-loaded crystals of high explosive material leads to the formation of hot spots, which, if hot enough, initiate chemical reactions. The collapse of microscopic pores contained within a crystal is one such process that localizes energy and generates hot spots. Given the difficulty of resolving the details of pore collapse in shock compression experiments, it is useful to study the problem using direct numerical simulation. In this work, we focus on simulating the shock-induced closure of a single pore in crystalline β-HMX using a multiphysics finite element code. To address coupled thermal-mechanical-chemical responses, the model incorporates a crystal-mechanics-based description of thermoelasto-viscoplasticity, the crystal melting behavior, and transformation kinetics for a single-step decomposition reaction. The model is applied to stress wave amplitudes of up to 11 GPa to study the details of pore collapse, energy localization, and the early stages of reaction initiation.