Simulation of RDX Decomposition Interacting with Shock Wave via Molecular Dynamics

Abstract

Cylotrimethylenetrinitramine (RDX), with the chemical formula C3H6N6O6,is an energetic organic molecule used widely in military and industrial commodities ofexplosives. By stimulating RDX through exerting temperature or mechanical conditionssuch as impact or friction, decomposition reaction occurs at a very high rate. Moleculardynamics techniques and LAMMPS code with Reactive Force Field (ReaxFF) potentialwere employed to simulate initiation of RDX. Potential energy variations of the systemwere calculated over time for five different temperatures up to 100 ps. The products ofdecomposed system with respect to time were calculated at each stage of stimulation fordifferent values of temperature and thermal initiation stimulation energy in NVT andNVE ensembles. The activation energy of decomposition was calculated 20.230kcal.mol-1 through Arrhenius equation. The minimum required temperature to produceH2 with temperature decomposition was about 2500 K and production times for severalconditions were calculated. The amount of nitrogen and hydrogen production wereincreased with raising temperature and reached the maximum value at 3000 K. Theminimum impetus energy required to form the light species H2 is 66 kcal.mol-1.`

Keywords

• rdx
• lammps
• molecular dynamics
• shock wave
• simulation