Impact Initiated Annular Retonation Wave in explosive

Abstract

Experiments conducted at the White Oak Laboratory with a pentolite explosive charge impacted by a flat‐ended cylinder of mild steel, showed a hole drilled at the center of the impactor, if the explosive was detonated. A computer simulation was carried out with the finite element hydrocode DEFEL and the Forest‐Fire reaction‐rate model. Computed results verified the hypothesis that the annular retonation was the cause of the drilled hole. The detonation started at a distance of about 10 mm from the impact surface, then developed into an annular shape and propagated inwards and backwards, to the axis of symmetry and the impact surface. The converging wave generated a pressure of about 100 GPa near the center of its impact surface, which is believed to be the real cause of the hole.