Atomic Insights into the Mechanical Sensitivity of Six Typical Explosives from Deep Potential Molecular Dynamics Simulation

Understanding the mechanical sensitivity of explosives remains challenging in experiments due to complex microscale kinetics under extreme conditions. Here, we employ deep potential molecular dynamics simulations (MD) based on first-principles calculations to explore the atomic-scale reaction dynamics trends in friction and impact sensitivity for six representative explosives (CL-20, HMX, RDX, TNT, NTO, and TATB). Shear MD simulations indicate that the initial and secondary reaction activation barriers strongly correlate to the experimental friction sensitivity rankings among the six explosives. Nonequilibrium MD (NEMD) shock simulations combined with Arrhenius analysis demonstrate that the final product generation rates dominate the impact sensitivity trends of the six explosives, and the initial reaction kinetics can only govern the impact sensitivity for more sensitive explosives like CL-20, HMX, and RDX. The mechanism difference between friction and impact sensitivity arises because friction-driven detonation is governed through the shear-induced stress-thermal coupling, where the conversion of shear strain energy into thermal excitation induces the decomposition of explosives. Although thermal activation occurs during the impact process as well, the remarkable compression effects suppress the carbon fragment formation, particularly in carbon-rich explosives like TNT, thereby reducing its impact sensitivity. The study establishes an insightful framework linking molecular architecture, reaction pathways, and macroscopic mechanical sensitivity, providing atomic-level insights into designing safer explosives.