Anisotropic modeling for shocked single crystals

A continuum, anisotropic modeling framework has been developed for simulating shock wave propagation in single crystals of arbitrary orientation. Our modeling approach incorporates nonlinear elasticity and crystal plasticity in a thermodynamically consistent tensor formulation. Crystal plasticity was described using models that consider dislocation motion along specified slip planes. Numerical simulations of large amplitude stress wave propagation in single crystals are presented. Using these simulations, issues related to pure mode propagation for nonlinear elastic waves are discussed. Also, the effects of plasticity on wave propagation in single crystals are examined by comparing simulations to wave profile data for copper and for LiF. For copper, a single dislocation model for slip on {111} planes provided good agreement with quartz gauge data for shocks along the [100], [110], and [111] directions. For LiF, slip occurs on {110} planes, and good agreement with data was obtained for shocks along the [100] direction. Using the same dislocation model, simulations were extended to shock wave propagation along the low symmetry [310] direction of LiF, where experimental data are not available. Propagation of quasilongitudinal and quasishear waves for this orientation are examined.