Intra- and Inter-Granular Hotspot Formation Mechanisms Under Shock Loading

In order to better understand and model the shock initiation and run to detonation processes, significant work has been performed over the last 6 decades to determine the fundamental mechanisms that govern hotspot formation. While significant progress has been made in this area, the underlying physics is highly convoluted and often material and microstructure dependent. However, over the last decade, rapid improvements in computing architecture has made it possible to study these phenomena with all-atom molecular dynamics (MD) at length and time scales that are nearing physically relevant to experimental studies macroscopic hydrocodes.

Here, I will discuss recent work on isolated mechanisms such as shear banding and hydrodynamic pore collapse, looking at the minutia processes than can end up causing significant effects at the macroscale. Followingly, this will be compared to results on inter-grain hotspot formation from coupled mechanisms using state-of-the-art MD simulations of packed granular systems. Lastly, we will explore the fundamental differences in intra- and inter-granular hotspot formation mechanisms in heterogeneous microstructures. The use of AI and ML techniques to deconvolute these processes will be discussed.