Publications
Unreacted equation of state development and multiphase modeling of dynamic compaction of low density hexanitrostilbene (HNS) pressings
Compaction waves in porous energetic materials have been shown to induce reaction under impact loading. In the past, simple two-state burn models such as the Arrhenius Burn model have been developed to predict slapper initiation in Hexanitrostilbene (HNS) pellets; however, a more sophisticated, fundamental approach is needed to predict the shock response during impact loading, especially in pellets that have been shown to have strong density gradients. The intergranular stress measures the resistance to bed compaction or the removal of void space due to particle packing and rearrangement. A constitutive model for the intergranular stress is needed for closure in the Baer-Nunziato (BN) multiphase mixture theory for reactive energetic materials. The intergranular stress was obtained from both quasi-static compaction experiments and from dynamic compaction experiments. Additionally, historical data and more recently acquired data for porous pellets compacted to high densities under shock loading were used for model assessment. Predicted particle velocity profiles under dynamic compaction were generally in good agreement with the experimental data. Hence, a multiphase model of HNS has been developed to extend current predictive capability.