A Mesomechanic Model Of Shock Initiation In Solid Heterogonous Explosives

In order to explain shock-to-detonation transition of heterogeneous solid explosives, several kinds of "hot-spot" formation mechanism and phenomenological models of shock initiation are investigated in this paper. A mesomechanic reaction model of heterogeneous explosives under shock wave is established on the basis of Kibong Kim's model, in which "hot spot" is formed as a result of the elastic-viscoplastic collapse induced by shock, while the growth stage starts from an inner combustion and is followed by an outer surface grain combustion.Genetic algorithms (GA), emulating the wonderful mechanism of evolution and natural selection of living organisms in nature, are regarded as one among the most promising optimization techniques. In this paper, the genetic algorithm is implemented to decide the model parameters in reaction rate of PBX9404, by using the stress histories recorded from Lagrangian gauges in a plane shock initiation experiment.The model has been implemented in one-dimensional reactive hydrodynamic program. It can be found that the improved model, with proper parameters, can predict SDT in "similar" explosives and explain the effects of properties of component explosive materials, initial particle size, initial porosity, initial temperature and the loaded stress on the explosive detonation initiation.