Plastic dissipation sensitivity to mechanical properties in polycrystalline β-HMX subjected to impact loading

Abstract

This manuscript investigates the sensitivity of plastic dissipation expressed in the form of temperature rise to anisotropic elasticity constants and crystal plasticity properties of crystalline β-HMX (1,3,5,7-tetranitro-1,3,5,7-tetrazocane) under impact loading conditions. Parametric sensitivity analyses are performed using a global sensitivity analysis framework to quantify the relative roles of the elasticity constants of the monoclinic β-HMX crystal, as well as to delineate thermal activation and phonon drag induced slip mechanisms that contribute to the nonlinear response. The plastic behavior of β-HMX is modeled using a Crystal Plasticity Finite Element model incorporating the slip mechanisms of thermal activation and phonon drag driven by the evolution of dislocation generation and annihilation. The results of the sensitivity analyses show that the anisotropic elasticity coefficients of the monoclinic crystal have a nominal effect on the energy dissipation and temperature rise, dominated by sensitivities of a few coefficients. Among the two primary slip mechanisms, phonon drag appears dominant within the load rate and amplitude regimes considered in this study.