Measurement of the shock initiation sensitivity of low density HMX

Abstract

The shock initiation sensitivity of HMX explosive at a density of 1.24 g/cm 3 (35% voids) was studied using cylindrical samples. Transit time measurements were taken at a number of sample thicknesses for a given input stress in order to determine run distance and time to detonation. The transit time data were subjected to a statistical analysis so that estimates of mean response were obtained along with estimates of the distribution in material response due to local variations in bulk density and particle size distribution. The statistical analysis is especially important when run distance to detonation becomes of the same order of magnitude as individual particle dimensions. The representation of the run distance/input stress data for these porous HMX samples in a log-log plot shows contrasting features with another low density explosive, PETN. Since the HMX and PETN data were obtained with different experimental configurations and had different particle size and shape distributions, more study is needed to reconcile contrasting aspects of shock initiation in highly porous explosives.