Equation of State for Multi-Functional Energetic Structural Materials

Abstract

Current investigations of multi-functional energetic structural materials (MESM) involve shock-induced and shock-assisted chemical reactions, in which complex physical processes are only elucidated by computational models of gas-gun experiments at the present time. The equation of state (EOS) is the one of the most important parts of the constitutive models incorporated into models that describe the processes in shock-induced and shockassisted chemical reactions. Implementation of current methods typically require many simplifying assumptions in the mixture rules. In this paper, two new EOS algorithms are proposed that i) can be used to physically interpret both homobaric and uniform strain assumptions, ii) do not require mixture averaged EOS parameters, and iii) do not have any restrictions on the form of constituent EOS or pore collapse model. Advantages of the proposed algorithms are discussed and comparisons are made with other mixture averaging methods. To demonstrate their use, a gas-gun experiment is simulated for a material with 2Al+Fe2O3 + 20 wt.% Epon828 + voids. The conservation equations and momentum balance are integrated in Eulerian coordinates using a second order finite volume scheme.