Dislocation-based plasticity for impact loading in solids

In this paper, a dislocation-based plasticity model is formulated in the framework of continuum mechanics and nonequilibrium thermodynamics for solids under high strain rates. Specifically, the formation of a dislocation network behind the shock front, associated plastic flow, resulting heating due to plastic work, and evolution of the morphology of the polycrystalline structure are modeled. The associated changes of dynamic strength or yield stress with the increasing shock strength due to nucleation of dislocations at the shock front are modeled. The microstructural characteristics of the dislocation network are modeled by selected internal state variables. The irreversible nonequilibrium processes at high strain rates are modeled by selected nonequilibrium state variables and their evolution equations. The results clearly show the increased localized heating due to increased dynamic strength and the associated plastic flow.