(U) The Effect of Initial Pressed Density on the Dynamic Densification Behavior of Brittle Granular Materials*

In this study, the effect of initial density ($\rho_{\mathrm{00}})$ on the dynamic densification behavior of a brittle granular system, cerium dioxide (CeO$_{\mathrm{2}})$, is investigated. Specifically, the consolidation behavior of pressed powder compacts at four initial pressed densities (33, 44, 55, {\&} 62.5{\%} TMD) is examined at densities within the compaction range via gas gun driven plate-on-plate impact. The shock Hugoniot data collected from these experiments are presented and used to calibrate P-$\alpha $ model parameters. The dependency of these P-$\alpha $ model parameters on initial density are presented and discussed.