A fully anisotropic single crystal model for high strain rate loading conditions with an application to α-RDX

In this paper, we develop a fully anisotropic, nonlinear, thermodynamically consistent model for single crystals under high rates of loading with thermodynamically consistent decoupling of the stress tensor into hydrostatic and deviatoric components. A new slip resistance model, which accounts for the main high-pressure mechanisms arising at the microscale including the effects of phonon drag, has been developed. When applied to α-RDX single crystals, the model is capable of predicting the salient elastic-plastic wave characteristics observed in gas gun experiments which include stress relaxation behind the elastic wave, elastic wave decay and increasing separation between the elastic and plastic waves with propagation. At lower pressures, slip activity is observed to occur over a longer period of time resulting in a distinct elastic plastic wave, which is missing at higher pressures.