Exploring Porosity Models for PBX-9501*

Porosity in high explosives (HE) noticeably alters aspects of their performance such as run-distance and time to detonation. Without porosity aware models to account for this change, any modeling effort would require new suites of experiments and calibration efforts for even small changes in density. This work involves investigating a hybrid P-alpha and small-lambda approach to model material response in the HMX-based explosive PBX 9501. This hybrid method has two steps. Using P-alpha along with the Davis reactants equation of state (EOS) at nominal density and known initial porosity is first used to compute the fully compacted EOS. Different initial densities are then considered as equilibrium mixtures of the fully compacted reactants with varying small amounts of Davis products. The Hugoniot of this mixture along with the material response to a range of particle speeds are investigated for model viability. The results of the material response from the hybrid model will be compared with available data from gas-gun experiments.