The influence of thermal damage and phase transition on impact and shock sensitivity in HMX systems

Drop-weight impact tests are a commonly used measure of explosive impact sensitivity. Often, simply the L50 of a given material is reported and compared with that of other materials to give a sense of its impact sensitivity. The practice of reporting the impact sensitivity as a single number, the L50, is likely inadequate. It is important to additionally report a measure of the spread of the distribution of reaction probabilities in order to assess the hazard of reaction in situations that may induce a stimulus level well below the L50 of a material. Additionally, multiple distribution forms have been suggested previously for fitting of binary sensitivity data; these distributions typically deviate from each other most near the tails (low and high stimulus levels). The consequences of choosing one distribution form over another in the analysis of explosive drop-weight impact results is explored.

Changes in impact sensitivity due to phase change have received some previous exploration, though the phase change influence is generally conflated with the induced damage upon said phase transition; however, sensitivity changes in the shock regime due to beta to delta-phase change have received little attention. Work is shown which includes methods to isolate variables of HMX phase transition and damage typically incurred upon said phase transition.