Double Hot Spots Mechanism in the crystalline RDX under the Overdriven Shock: A Reactive Molecular Dynamic Simulation Study

Hot spots resulted from shock-induced void collapse could seriously alter the ignition and initial chemical reactions in heterogeneous explosive crystals. Herein, the effects of hot spot distance on ignition and reaction growth in the crystalline RDX were investigated through reactive molecular dynamics simulations based on LAMMPS codes. This work uncovers that the farther double hot spots result in the more RDX molecules being heated simultaneously and then reacted quickly under the synergetic growth of double hot spots. The farther hot spot distance leads to a faster decomposition degree of RDX molecules, a higher concentration of NO2 liberation, and even greater violent growth for explosive reaction, which indicates RDX with a longer void-void distance is more sensitive to the present overdriven shock. In terms of the synergetic growth of double hot spots, it is demonstrated that reducing hot spot distance could result in decreasing the high-temperature area ratio in the crystalline RDX exposed to an overdriven insult, avoiding the occurrence of a greater violent scenario. The current work sheds light on an interesting view of comprehending the nanoscale voids interaction, shock-induced ignition and chemical decomposition in the crystalline explosives.