Three Dimensional Analysis of Induced Detonation of Cased Explosive

Fragments of aluminum impacting on Composition B explosive encased in rolled homogenous armour (RHA) steel were investigated through the LS-DYNA®. The investigation focused on shock to detonation simulations of Composition B, with the objective of determining both the critical velocity which would generate a shockwave strong enough to cause detonation of the explosive, as well as the resulting pressure profile of the detonation wave. Detonation scenarios at low, intermediate and high impact velocities were investigated. It was observed that at low impact velocity the explosive failed to detonate. At intermediate velocities, detonation was due to the development of localized hot spots caused by the compression of the explosive from the initial shockwave. Detonation was also caused by pressure waves reflecting against the casing of the explosive leading to the so-called sympathetic detonation. At high impact velocity, initiation of the explosive was caused by the initial incident pressure wave located immediately behind the top casing/explosive interface.