HMX/TNT Interfacial Properties from Molecular Dynamics Simulations: Energetics, Rheology, and Molecular Structure

Interfacial properties and interactions between crystals and binders play a critical role in the initiation of high explosive (HE) systems. This role is explored through molecular dynamics simulations of the octol system, consisting of octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) grains and 2,4,6-trinitrotoluene (TNT) as a binder. A flexible, non-reactive, force field was developed building upon existing TNT and HMX force fields. Cross terms and intra-molecular terms for TNT were optimized using equations of state, vibrational normal mode data, and the DFT calculations for HMX and TNT molecule interactions. We use this force field with molecular dynamics to characterize the energetics, rheological, and structural properties of HMX-TNT interfaces and interphases.