Numerical simulation of shock wave propagation in spatially-resolved particle systems

The shock compression of spatially-resolved particle systems is studied at the mesoscale through a series of finite element simulations. The simulations involve propagating shock waves through aluminium–iron oxide thermite systems (Al+Fe2O3) composed of micron-size particles suspended in a polymer binder. Shock-induced chemical reactions are not considered in this work; the particle systems are modelled as inert mixtures. Eulerian formulations are used to accommodate the highly dynamic nature of particulate shock compression. The stress–strain responses of the constituent phases are modelled explicitly at high strain rates and elevated temperatures. Dynamic behaviour of the model system is computed for a set of mixtures (20% and 50% epoxy content by weight) subjected to a range of loading conditions (particle velocities that span 0.300– 1.700 km s−1). Spatial profiles of pressure and temperature obtained from the numerical simulations provide insight into thermomechanical responses at the particle level; such resolution is not available in experiments. Finally, Hugoniot data are calculated for the particle mixtures. Stationary pressure calculations are in excellent agreement with experiments, while shock velocity calculations exhibit larger deviations due to the 2D approximation of the microstructure.