Molecular dynamics study of dynamic responses of glassy silica under shock impact

In this study, molecular dynamics (MD) simulations are performed to form glassy silica from melted b-cristobalite using cooling rates of 2, 20 and 200 K/ps. The resulting glassy silica samples are then shocked at particle velocities ranging from 0.3 to 11 km/s in the MD simulations. The effect of the cooling rate on the shock wave velocity is observed for particle velocities below 2 km/s. Moreover, the simulated pressure and density of the shocked glassy silica increase as the cooling rate increases. As compared with the experimental data, the MD simulation can approximately identify the initiation of densification and predict the shock wave velocity within the reasonable accuracy. The simulated pressure and density of the shocked silica match the experimental and EOS analysis data well when the shock pressure is below 500 GPa. However, the proposedMDsimulations under-estimate the density when the glass is shocked at pressures above 500 GPa, which indicates that a better interatomic potential model is required for modeling silica under ultrahigh pressures. © 2010 Tech Science Press.