Shock Initiation of Solid Explosives

Abstract

Initiation phenomena in solid explosives produced by strong shock waves are described. Shock pressures in the explosive are between 20 and 200 kbar. It is demonstrated that in the usual case the shock wave travels not as an inert shock, but as a shock to which the explosive contributes energy, probably from reaction at voids and defects. This slightly reacting shock travels at increasing velocity for some distance, typically 1 cm in the experiments described, and then in a travel of perhaps 0.01 cm becomes full detonation, moving at full velocity. The increase to full detonation velocity occurs without overshoot. Experiments demonstrating the variation of sensitivity to shock with density, grain size, and other properties are discussed. The explosives studied are cyclotol B, TNT, plastic-bonded HMX, and nitromethane-carborundum mixtures.

Analysis of Shock Wave and Initiation Data for Solid Explosives

“…They also showed that the intercept for zero particle velocity is the bulk sound velocity. The bulk velocity is defined by equation (1) c = (k/p )! …”

Nanocrystalline trinitrotoluene (TNT) using sol–gel process

“…The detonation behaviour of explosive materials is influenced by their microstructural features like particle size distribution, shape and surface area [1][2][3]. The secondary explosives developed with reduced particle size tend to be more insensitive for mechanical stimuli and may release energy with faster rate [4,5].…”

Desensitization by Pre-shocking in Heterogeneous Explosives and its Numerical Modelling

“…As early as 1960, Campbell et al [1] reported that a 3.9 GPa preshock desensitized a plasticbonded HMX explosive to initiation by a following 10 GPa shock. In a later study, Campbell and Travis [2] desensitized PBX-9404 and Composition B-3 by subjecting them to pre-shocks in the pressure range 1.0-2.4 GPa.…”