Hot spot formation and shock initiation of RDX*

Hot spot formation mechanism in energetic materials (EM) is crucial to handling and design of safer explosives. Presence of defects such as cracks, voids and grain boundaries are mainly responsible for creation of extreme conditions leading to hot spots. Recent experimental studies have shown that the presence of filled and empty void in EMs are responsible for creation of these regions. Here, we present a million-atom reactive molecular dynamics study to investigate the nature of hot spots during shock compression of RDX in gas filled and empty voids. We observe higher and sustained temperature rise in gas filled voids as compared to empty voids at particle velocities ranging from 2-4 km/sec. Furthermore, we observe that the higher amount of heat release on account of high potential energy drop in gas-filled voids correlate positively to more stable fragment formation, hence validating its role in high impact shock initiation of RDX.