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Using nonequilibrium molecular dynamics (MD) simulations we study shock-induced melting in Ni with an embedded atom method (EAM). Dynamic melting is probed by the pair correlation function, and we find a melting lattice temperature of T-melt=6400 +/- 300 K for a melting pressure of P-melt=275 +/- 10 GPa. When a combined MD+TTM (two-temperature model) approach is used to include electronic heat conduction and electron-phonon coupling, P-melt and T-melt change. For a given pressure, the temperature behind the shock decreases due to electronic heat diffusion into the cold, unshocked material. This cooling of the material behind the shock slightly increases the melting pressure compared to simulations without electronic heat conduction and electron-phonon coupling. The decrease in the temperature behind the shock front is enhanced if the electron-phonon coupling is artificially made larger. We also explore the feasibility of using x-ray diffraction to detect melting., QC 20100525

Since ceramics are quite brittle they cannot be used alone as passive elements in vehicle armors because of multi-hit requirements. Consequently, layers of ceramic tiles embedded in more ductile metals are usually employed for this purpose. The performance of such arrays depends heavily on the geometry and materials used. To shorten the search for suitable arrangements, computer simulations can be alternated with experiments. Here we will discuss some current efforts to simulate the ballistic performance of ceramics against kinetic energy threats. Kinetic energy projectiles, Armored vehicles, Mathematical model