Simple model to explain inhomogeneous structures in shocked solids

A model is proposed to explain observations of inhomogeneous yielding in shocked solids. Instead of seeking hydrodynamic or elastic-plastic instabilities in an initially homogeneous specimen, it is proposed that the material under shock conditions (at pressures well above the yield strength) may be characterized as a viscous medium with initially inhomogeneous viscosity. Such a viscosity might be caused by an inhomogeneous distribution of dislocations. Assuming that the viscosity also decreases with temperature in a simple way, suitably truncated hydrodynamic equations can be solved analytically and predict a tendency toward runaway of temperature and deformation in localized regions.