Constituent properties of HMX needed for mesoscale simulations

Plastic-bonded explosives are heterogeneous materials. Improved burn models for weak initiation relevant to accident scenarios require a better understanding of the physics associated with the formation and growth of hot spots. Since the relevant length scale is subgrain in extent, mesoscale simulations are needed to study hot spots. Mesoscale simulations require as input constitutive properties of an explosive grain. In addition, it is essential to account for physical dissipative mechanisms since hot spots represent local peaks in the fluctuations of the temperature field. Here, constitutive properties of the explosive HMX needed for mesoscale simulations are discussed and experimental data reviewed. Because some decomposition may occur during a measurement, it is difficult to account for systematic error in the data. To get a sense of the uncertainties in material parameters, it is necessary to examine all the available data. In addition, we discuss results from molecular dynamics simulations of some properties for which experimental data are lacking.