Shock Wave Structuring Viscosity: The Nuclear Ground Shock and Shock Compaction of Granular Solids

Addressed is the underlying solid viscosity responsible for the structure and time history of shock waves in solid matter. Application is to nuclear ground shocks in rock salt geology and laboratory compaction shock waves in granular material. In both applications attenuating shock wave measurements are pursued that exhibit transient steady wave behavior. Shock viscosities are extracted from shock wave measurements. Causes underlying shock viscosity are identified with structural relaxation and kinetic dissipation. Both the ground shock and compaction shock measurement demonstrate near elastic compression wave response. Calculations applying a viscoelastic relaxation model replicate measured steady wave shock structure. Shock wave viscosity and time history measurements are expanded to additional solid and granular materials for purposes of identifying systematics. A systematic dependence of granular material shock compaction viscosity on granular particle size is identified. Constancy of the product of the steady wave rise time and the viscous dissipation energy, identified as the dissipative action, is noted for both solid and granular material shock compaction. Dissipative action as an adiabatic invariant is compared with action in the nonlinear dynamics of ocean waves.