Determination of Delay in Detonation of a Sandwiched Explosive Impacted by a Shaped Charge Jet

A simple analytical model has been developed to determine delay in detonation of an explosive sandwiched between two metal plates and impacted by a shaped charge jet. The analytical model consists of a relation between detonation delay and depth of jet penetration in a target kept in contact across the explosive sandwich. This relation is derived by expressing depth of jet penetration P as a function of detonation delay Tdx and duration Tw of free passage of the jet through the hole in the top plate of the sandwich. One more relation between Tdx and Tw has been obtained from the theory of expansion of hole produced in a metal plate by jet impact. These two relations have been solved simultaneously to get values of both these parameters as a function of jet penetration. It is proposed that this analytical model can be used in two ways. First, this model can be used to calculate detonation delay by experimental measurement of jet penetration in a target. The detonation delay thus determined can be used to calculate insensitivity constant Aj of an explosive. Second, this model can be used to theoretically calculate jet penetrations obtained by different shaped charge warheads when using a sandwich of explosive with a given insensitivity. Both uses of this analytical model are illustrated using numerical examples.