Low-velocity impact sensitivity of HMX-based explosive compositions

A numerical study of the heat generated by plasticity during the impact of a confined HMX-based PBX is detailed. It includes a literature review and previous experimental investigations at microscale and mesoscale. A crystal plasticity model has been implemented in an explicit solver to simulate polycristals submitted to shear. Using literature data for the HMX behaviour enables reproducing the mean stress-strain curve observed during quasi-static triaxial experiments at 0.8 GPa. Results from fifteen polycrystals have been used to relate the maximum local temperature to the macroscopic plastic shear strain. This localization rule has been used to predict initiation during low-velocity impacts of pyrotechnic structures incorporating HMX-based PBX.