Molecular-level Analysis of Shock-wave Physics and Derivation of the Hugoniot Relations for Soda-lime Glass
ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD SURVIVABILITY MATERIALS BRANCH
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Non-equilibrium and equilibrium molecular dynamics simulations are employed to study the mechanical response of soda-lime glass a material commonly used in transparent armor applications when subjected to the loading conditions associated with the generation and propagation of planar shock waves. Particular attention is given to the identification and characterization of various inelastic-deformation and energy-dissipation molecular-level phenomena and processes taking place at the shock front. The results obtained revealed that the shock loading causes a 2 4 shock strength-dependent density increase. In addition, an increase in the average coordination number of the silicon atoms is observed along with the creation of smaller Si O rings. These processes are associated with significant energy absorption and dissipation and are believed to control the blastballistic impact mitigation potential of soda-lime glass. This study was also aimed at the determination via purely computational means of the shock Hugoniot i.e., a set of axial stress vs. densityspecific-volume vs. internal energy vs. particle velocity vs. temperature material states obtained in soda-lime glass after the passage of a shock wave of a given strength and on the comparison of the computed results with their experimental counterparts. The availability of a shock Hugoniot is critical for construction of a high deformation-rate, large-strain, high pressure material model which can be used within a continuum-level computational analysis to capture the response of a soda-lime glass-based laminated transparent armor structure e.g., a military vehicle windshield, door window, etc. to blast ballistic impact loading.
- Ceramics, Refractories and Glass
- Numerical Mathematics
- Fluid Mechanics
- Atomic and Molecular Physics and Spectroscopy