Shear localization and its effect on shock-induced reactive pore collapse using atomistics-consistent material models

Microstructures of energetic materials exhibit defects including pores, cracks, and delaminated interfaces, all of which act as sites for energy localization under shock loading. Previous mesoscale simulations of reactive hotspot formation have relied on material models that inadequately captured key aspects of material behavior, including thermophysical properties and material strength. Our recent work has advanced the modeling and understanding of pore collapse in HMX under shock loading by employing atomistics consistent models, demonstrating that continuum calculations using these models yield pore collapse and hotspot formation closely aligned with molecular dynamics results. In this study, we utilize high-fidelity mesoscale simulations to reassess hotspot evolution and energy localization with the latest atomistic-consistent material models for HMX. These refined models reveal significant differences in hotspot development at pore collapse sites and uncover new physics associated with energy localization along shear bands. We compare mesoscale energy localization rates with previous mesoscale calculations, quantitatively evaluating the resulting differences. This work advances both the physical understanding and quantitative prediction of hotspot ignition and growth rates in HMX, contributing to the development of improved mesoscale-informed reactive burn models for sensitivity prediction in energetic materials.