Measure of Dynamic Toughness Parameters for High Explosive Mock Material Using Instrumented Charpy Impacts

摘要

Material parameters for high explosives are required for predicting the onset of failure and intensity of fragmentation resulting from high velocity impact events. The mechanical breakup associated with dynamic loading influences both the bulk mechanical and chemical material behaviors, thus altering their sensitivity to reaction initiation. For instance, interfacial debonding between the energetic crystals and polymeric binder can enhance the formation of hot spots, thus triggering detonations at relatively low-level-loading conditions. Conversely, the mechanical breakup may inhibit the propagation of the detonation wave through a discontinuous solid and diminish the reaction behavior or sensitivity to reaction initiation. The challenge is to understand the synergistic behavior between mechanical and chemical properties that influence the overall bulk material response from a mechanical insult with the microstructural features of the explosive crystals and binder phase. Therefore, it is necessary to devise a method for extracting dynamic toughness and fracture parameters that can be used for the development and validation of computational models.