Multiscale Modeling of Shock Wave Localization in Porous Energetic Material

TL;DR

This study combines molecular dynamics and mesoscale simulations to understand how shock waves interact with pores in energetic materials, revealing different behaviors under weak and strong shock conditions.

Contribution

It introduces a multiscale modeling approach that links atomistic pore collapse simulations with mesoscale hydrodynamic models for energetic materials.

Findings

Weak shocks cause different pore collapse behavior than strong shocks.

The combined modeling approach constrains mesoscale parameters physically.

Pore collapse dynamics vary significantly with shock strength.

Abstract

Shock wave interactions with defects, such as pores, are known to play a key role in the chemical initiation of energetic materials. The shock response of hexanitrostilbene is studied through a combination of large scale reactive molecular dynamics and mesoscale hydrodynamic simulations. In order to extend our simulation capability at the mesoscale to include weak shock conditions (< 6 GPa), atomistic simulations of pore collapse are used to define a strain rate dependent strength model. Comparing these simulation methods allows us to impose physically-reasonable constraints on the mesoscale model parameters. In doing so, we have been able to study shock waves interacting with pores as a function of this viscoplastic material response. We find that the pore collapse behavior of weak shocks is characteristically different to that of strong shocks.