Coupling Effect of Shock, Heat, and Defect on the Decay of Energetic Materials: A Case of Reactive Molecular Dynamics Simulations on 1,3,5-Trinitro-1,3,5-triazinane

Multiple types of external stimuli are usually loaded on an energetic material (EM) simultaneously, and thus they have a coupled effect on its decay. Meanwhile, the structures of the EM essentially influence the decay. Thereby, the coupling effects of these stimuli and structures should be considered in assessing the decay and further the safety of EMs. Nevertheless, it is still difficult to clarify the atomistic/molecular details of the coupling effects on the decay and safety mechanisms. In the present work, we perform reactive molecular dynamics simulations in combination with the multiscale shock technique to reveal a shock preheating dislocation coupling effect on the decay mechanism of an energetic representative, 1,3,S-trinitro-1,3,5-triazinane (RDX). That is, three factors including shock velocity, preheating temperature, and edge dislocation are accounted as variables for the simulations. Increasing shock velocity and preheating temperature and presenting edge dislocation in crystal both promote the RDX decay. Preheating enhances the shock sensitivity as ascertained experimentally, and the sensitivity enhancement is caused by the elevated potential energy of the RDX molecules because of preheating. Moreover, interestingly, two different shock-preheating dislocation couplings can possess an equivalent effect on the RDX decay, as they can lead to almost same evolutions of major chemical species, temperature, pressure, and potential energy. All these findings are expected to deepen the insight into the response mechanisms for the EMs against external stimuli, particularly in the case of multiple factors coupled.