Application of Crystal Lattice Disintegration Criteria to Compute Minimum Shock induced reactive conditions in solid explosives and inert materials

Abstract

A threshold particle velocity criteria derived by E.R. Fitzgerald for the beginning of crystal lattice breakup and disintegration has been applied to shocked explosives and an inert material. In shocked explosives, reactions leading to detonation occur above a certain “threshold” magnitude. The computed crystal lattice breakup shock pressures compare rather well with observed experimental “threshold” shock pressures for six high explosives. The six explosives are: Comp‐B3, Comp‐B, TNT, PBX‐9404, Tetryl, and H‐6. In addition, the crystal lattice breakup criteria provides an explanation for the observed lowering of the detonation “threshold” shock pressure as the explosives are made more porous or less dense. Finally, the shock pressures, at which output from thermocouples embedded in shocked materials (PBX‐9404 and Plexiglass) increases dramatically, compare favorably with predictions based on crystal lattice disintegration criteria. Consequently, it is tentatively concluded that crystal lattice breakup, or self‐sustained phonon fission as Fitzgerald calls it, is responsible for the initiation of detonation in shocked explosives and enhanced thermocouple output in shocked materials. It is also postulated that the lattice breakup phenomena is also responsible for phase changes, increased chemical reactivity, and anomalous electrical activity which are observed in certain inert materials under relatively low level shock loading.