Simulation study of shock reaction on porous material

TL;DR

This study uses the material-point method to analyze how shock strength and porosity affect the behavior of porous materials, revealing mechanisms of energy transformation and dynamic responses under shock loading.

Contribution

It introduces a simulation approach to study shock effects on porous materials, highlighting the influence of porosity size and shock strength on their dynamic response.

Findings

Local turbulence and volume dissipation convert kinetic energy to heat.

Small porosity leads to steady shock states with oscillations due to wave reflections.

Larger mean-void-size results in higher mean temperature for the same porosity.

Abstract

Direct modeling of porous materials under shock is a complex issue. We investigate such a system via the newly developed material-point method. The effects of shock strength and porosity size are the main concerns. For the same porosity, the effects of mean-void-size are checked. It is found that, local turbulence mixing and volume dissipation are two important mechanisms for transformation of kinetic energy to heat. When the porosity is very small, the shocked portion may arrive at a dynamical steady state; the voids in the downstream portion reflect back rarefactive waves and result in slight oscillations of mean density and pressure; for the same value of porosity, a larger mean-void-size makes a higher mean temperature. When the porosity becomes large, hydrodynamic quantities vary with time during the whole shock-loading procedure: after the initial stage, the mean density and pressure decrease, but the temperature increases with a higher rate. The distributions of local density, pressure, temperature and particle-velocity are generally non-Gaussian and vary with time. The changing rates depend on the porosity value, mean-void-size and shock strength. The stronger the loaded shock, the stronger the porosity effects. This work provides a supplement to experiments for the very quick procedures and reveals more fundamental mechanisms in energy and momentum transportation.