Molecular dynamics of shock waves in three-dimensional solids: Transition from nonsteady to steady waves in perfect crystals and implications for the Rankine-Hugoniot conditions

Molecular-dynamics calculations of shock waves in perfect three-dimensional solids at nonzero initial temperatures reveal a transition in the nature of the asymptotic shock-wave structure as a function of shock strength. The key to this transition from nonsteady to steady waves where the Rankine-Hugoniot relations are obeyed is the partial relaxation of compressive shear stress behind the shock front which accompanies small, but permanent, transverse strains in atomic positions.