Abstract: The effect of crystal structure of high density spherical RDX on the safety of PBX was studied by molecular dynamics simulation and experiment. The crystal structure of high density spherical RDX was measured by X-ray single crystal diffraction. Then based on the crystal structure data, the safety performances of high density spherical RDX-based PBX and ordinary RDX-based PBX were compared by molecular dynamics simulation. To verify the accuracy of molecular dynamics simulation results, the casting PBX explosives based on high density spherical RDX and ordinary RDX were prepared. The detonator sensitivity and shock wave sensitivity of the casting PBX were tested by using direct detonation method and card separator method. Molecular dynamics simulated and experimental results show that the high density spherical RDX is a monocrystal with few internal defects and spherical shape, and its cell density is 2.6% higher than that of ordinary RDX. The binding energy of high density spherical RDX-based PBX is 289.30 kJ·mol^-1 higher than that of ordinary RDX-based PBX, the cohesive energy density is increased by 0.022 kJ·cm^-3, and the maximum bond length of the induced bond is reduced by 0.02 , indicating that it has lower sensitivity. For the same formula, the detonator sensitivity and shock wave sensitivity of the high density spherical RDX-based PBX are lower than those of the ordinary RDX-based PBX, which is consistent with the results of molecular dynamics simulation. The simulated results were verified to be accurate.Key

Key words: highdensitysphericalRDX, polymerbondedexplosive, crystalstructure, moleculardynamicssimulation, explosivesensitivity