Molecular dynamics simulations of shock wave propagation in single crystal copper

Various regimes of shock wave propagation, including both elastic-plastic split-shock waves and single two-zone elastic-plastic shock waves, were studied by molecular dynamics (MD) simulations in single crystal copper oriented along the \textless 100\textgreater , \textless 110\textgreater , and \textless 111\textgreater\ directions using both traditional piston-driven and the newly developed moving window MD techniques. The single two-zone elastic-plastic shock wave consists of the elastic zone followed by a plastic zone, where both elastic and plastic fronts move with the same speed, thus maintaining on average a constant separation. Although the properties of the leading elastic zone in both split-shock wave and single two-zone regimes are orientation-dependent, the thermodynamic properties of the plastic state are not once the steady-state regime is achieved in micrometer-thick films. The orientation-independent plastic Hugoniot obtained in our MD simulations agree with experimental observations of orientation-independent shock-wave propagation in single crystal copper [1].\\[4pt] [1] R. Chau, J. St\"{o}lken, P. Asoka-Kumar, M. Kumar, and N. C. Holmes, J. Appl. Phys. 107, 023506 (2010).