Visualization of PBX responseto impact loading

The safety and reliability of energetic materials (EM) is of great importance in many industries including mining, oil drilling, and weapons. The understanding of the critical loading conditions and mechanisms that drive the detonation of EM is crucial to ensuring that they are consistently safe and reliable. In this study impact experiments were performed on Plastic-Bonded Explosive (PBX) samples, which are composites consisting of HMX (cyclotetramethylene tetranitramine) crystals inside a Sylgard 184 binder, using a single stage, smooth bore, light gas gun. Impact velocities varied, but were around 420 m/s High-speed x-ray phase contrast videos were recorded during the experiments and then analyzed to characterize crystal behavior under the given experimental conditions. The videos showed two main responses the crystals exhibited when impacted. These are fracture and expansion. The crystal expansion is thought to be the result of chemical reaction in the crystal. The samples do not have enough mass or length to reach detonation, but hot spot formation and chemical reaction are still possible and of interest.