ReaxFF molecular dynamics study on the shock-induced initiation mechanisms of ordered and disordered TNT/CL-20 coated models

The atomic-scale initiation mechanisms of energetic composites under shock loading represent a fundamental top in detonation physics. In this work, ReaxFF- lg reactive molecular dynamics were employed to investigate the shock responses of ordered and disordered TNT/CL-20 coated models under various shock velocities. Results show that molecular packing governs energy transfer: ordered systems exhibit faster shock waves, whereas disordered systems undergo more localized heating during compression. Analyses of decomposition reactions reveals that TNT dimerization dominates the initial reaction, followed by TNT-CL-20 polymerization at lower shock intensities. Notably, ordered structures accelerate reaction onset and enhance CL-20 consumption. Product evolution strongly depends on shock velocity: small-molecule products such as CO 2 and CO increase with higher velocities, while the formation of some intermediate species displays distinct non-monotonic trends. The decomposition pathways also differ: ordered packing facilitates rapid energy release via sequential reactions, while disordered packing favors thermal fragmentation. Fitted detonation pressures confirm that coated models exhibit perform between the pure components. These findings demonstrate that molecular-scale structural order significantly influences both dynamic response and chemical reactivity, offering mechanistic insights for designing tunable melt-cast explosives with tailored sensitivity and energy output.