The effect of failure diameter on the initiation of explosives by shaped charge jets

Abstract

Experiments on two explosives, where the selected shaped charge jet had a diameter that was larger than the failure diameter for the HMX-based explosive, but much smaller than the failure diameter of the TATB-based explosive, show similarities in the initiation behaviour generated by the impact shock. In this "prompt" shock initiation regime both explosives show similar lengthening of run distances when the jet impacts approach the initiation threshold. Theoretical investigations using the CREST reactive burn model showed that reaction started reasonably promptly across the diameter of the jet in both explosives, and in the case of the jet being smaller than the failure diameter, the extended runs were due to the delay in corner turning out of this restricted diameter experienced by the detonation in the TATB composition. For the HMX composition, the rather sparse number of results appears to compare with regular projectile data which show increased run distances as the projectile diameter approaches the failure diameter. More work is required to establish the exact mechanism in this regime. © 2012 American Institute of Physics.