MOLECULAR-DYNAMICS INVESTIGATION OF THE DESENSITIZATION OF DETONABLE MATERIAL

A molecular-dynamics investigation of the effects of a diluent on the detonation of a model crystalline explosive is presented. The diluent, a heavy material that cannot exothermally react with any species of t he system, is inserted into the crystalline explosive in two ways. The first series of simulations investigates the attenuation of the energ y of a detonation wave in a pure explosive after it encounters a small layer of crystalline diluent that has been inserted into the lattice of the pure explosive. After the shock wave has traversed the diluent layer, it reenters the pure explosive. Unsupported detonation is not r eestablished unless the energy of the detonation wave exceeds a thresh old value. The second series of simulations investigates detonation of solid solutions of different concentrations of the explosive and dilu ent. For both types of simulations, the key to reestablishing or reach ing unsupported detonation is the attainment of a critical number dens ity behind the shock front. Once this critical density is reached, the explosive molecules make a transition to an atomic phase. This is the first step in the reaction mechanism that lends to the heat release t hat sustains the detonation. The reactive fragments formed from the at omization of the heteronuclear reactants subsequently combine with new partners, with homonuclear product formation exothermally favored. Th e results of detonation of the explosive-diluent crystals are consiste nt with those presented in an earlier study on detonation of pure expl osive [B. M. Rice, W. Mattson, J. Grosh, and S. F. Trevino, Phys. Rev. E 53, 611 (1996)].