Shock Initiation Thresholds of Heterogeneous Explosives with Elastic-Visco-Plastic Hot Spot Model

The initiation criterion of heterogeneous explosives is important for weapon design and safety evaluation.In this paper, based on Kim's elastic-visco-plastic "hot-spot" model, we numerically solved a temperature rising model of a local hot-spot inside the explosive, and obtained the initiation thresholds for TATB and HMX under different shock loading pressures.We quantitatively analyzed the influence of explosives' porosities on the shock initiation thresholds, and compared the calculated thresholds with experimental results.We drew the following conclusions:under a pressure of 1-10 GPa, the calculated initiation thresholds agree well with the one-dimensional shock initiation experimental results; the corresponding initiation thresholds of the explosives are approximately constant; under a pressure above 10 GPa, as the pressure rises gradually, the dominant shock initiation mechanism of the heterogeneous explosives transforms from the uneven heating of the local hot spot, to the shock's direct heating of the bulk of the explosive.Furthermore, we also verified that, within a given pressure range, the initiation threshold dropped as the explosives' porosities increased.