Shock Structure and Equilibrium States of Epoxy-Spinel and Porous Cu-W Mixtures Employing a New, Multi-Material Continuum Mixture Model

A new, Baer-Nunizato type multi-material continuum mixture model is leveraged to explore the shock structure and equilibrium states of epoxy-spinel and copper-tungsten mixtures subjected to plate impact conditions. The theory is symmetric in regard to material appearance and is formulated to handle an arbitrary number of materials in three-dimensions. Based on pairwise interactions of component materials, relaxation parameters controlling the rates of velocity and pressure equilibration are varied to investigate the sensitivity of shock structure and equilibrium states to both momentum and energy exchange and to the evolution in solid volume fraction. Model validation and verification are provided by comparison of simulation results with experimental data and numerical results of Bdzil et al. 2021 for the epoxy-spinel mixture. The capability of the model to predict the effects of porosity on shock equilibrium states is demonstrated for porous copper, porous tungsten, and porous copper-tungsten mixtures, and compared to experimental data.