Molecular-Level Analysis of Shock-Wave Physics and Derivation of the Hugoniot Relations for Fused Silica

作者：Grujicic M^*; Pandurangan B; Zhang Z; Bell W C; Gazonas G A; Patel P; Cheeseman B A

来源：Journal of Materials Engineering and Performance, 2012, 21(6): 823-836.

DOI：10.1007/s11665-011-0005-2

• fused silica
• Hugoniots
• non-equilibrium molecular-dynamics simulations
• shock waves

Equilibrium and non-equilibrium molecular-dynamics simulations are employed in this study to investigate various aspects of shock waves in fused silica (a pure SiO2 amorphous material used in transparent-armor applications). Equilibrium molecular-dynamics simulations are used first to validate that the initial (unshocked) fused silica possesses the appropriate mass density and microstructure (as characterized by its partial Si-Si, Si-O, and O-O radial distribution functions). Next, non-equilibrium molecular-dynamics simulations are employed, within a continuously contracting computational-cell scheme, to generate planar longitudinal (uniaxial motion) shocks of different strengths. By examining and quantifying the dynamics of shock-wave motion, the respective shock-Hugoniot relations (i.e., functional relations between various material-state variables in the material states produced by the shocks of different strengths) are determined. This methodology suggested that irreversible non-equilibrium deformation/damage processes play an important role in the mechanical response of fused silica to shock loading and that the %26quot;equilibrium%26quot; procedures for Hugoniot determination based on the equation of state and the Rankine-Hugoniot equation may not be fully justified. Finally, the non-equilibrium molecular-dynamics simulations were used to identify the main microstructure modifying/altering processes accompanying the shock-wave motion through fused silica.

• 出版日期2012-6