Development and modeling for a small-scale, rapid heated explosives experiment

Most small-scale tests of explosive sensitivity, the drop-weight test in particular, convolute so many complex phenomena that it has been extremely challenging to decipher how an explosive ignites and propagates reactions. For instance, an impact generates heat through a range of dissipation mechanisms, which can in turn, depending on the reaction rates of the explosive, lead to chemical decomposition. In order to deconvolute the various contributions to the sub-shock initiation and propagation of explosive reactions, we will discuss the development and modeling of the High Explosives Initiation Time (HEIT) test - a new, small-scale, high throughput experiment designed to rapidly heat small quantities of energetic materials within small diameter steel needles. Specifically, we have designed and modeled a 250 Joule pulsed power system capable of rapidly delivering electrical current to the needles, resulting in rapid heat delivery to the sample. The energy rate deposition into the needle is controlled by different transmission line topologies. Modeling in COMSOL is performed to understand the energy required to heat up the explosive sample, and the electrical current is modeled as a decaying sinusoid.