Abstract:
This report details the use of computational models to simulate the grain-scale dynamics of explosives, with the goal of developing more realistic and predictive material models for use in hydrodynamics/multi-physics codes. The project focuses on understanding how the heterogeneous nature of explosives—composed of crystals and a plastic binder—influences their response to external stimuli like shock waves. The research aims to establish a direct link between grain-scale characteristics (e.g., grain size, void shape, binder properties) and the macroscopic performance and safety of explosives. The document describes the development of an initial reactive flow model that incorporates insights from these grain-scale simulations. It explains the importance of shock waves collapsing voids within the material, which creates hot spots that initiate chemical reactions. The study uses the ALE-3D software to perform these simulations and addresses challenges such as accurately representing the complex geometry of the explosives and modeling the propagation of deflagration at high pressures. The work highlights several key achievements, including deriving a mixture rule for computational zones, inferring a form factor from hot spot simulations, and applying the new model to calculate detonation in small-diameter explosive cylinders. It also identifies future research needs, such as resolving discrepancies between numerical simulations and experimental deflagration rates and understanding the effect of binder materials on detonation.
