A computational study of microstructure effects on shock ignition sensitivity of pressed RDX

There are many experimental measurements of microstructure effects on shock sensitivity and performance of solid explosives. But comparatively speaking, there are very few numerical models of these effects. This paper presents a computational experiment of microstructure effects using a recently developed model (Y. Hamate and Y. Horie, Shock Waves, V. 16, 125 (2006)). The model has been developed aiming at expanding predictive capability and applicability. To increase model capability, it is important to focus on physics-based approach, rather than parameter-fitting approach where non-physical parameter(s) needs to be re-calibrated for different set of conditions. Our model explicitly treats specific surface area with an assumption of exponential size distribution of hot-spots. Experimentally, Khasainov et al. discussed effects of specific surface area and found that both run distance to detonation and critical diameter have linear relation with reciprocal of specific surface area of HE. Computational experiments are carried out using pressed RDX model with various initial specific surface areas that are determined by average explosives particle size. The results demonstrate that both Pop-plots and critical diameter show the linear relation as observed by Khasainov et. al.