Fragment Velocities from Thermobaric Explosives in Metal Cylinders

Abstract

Abstract Thermobaric explosives (TBXs) have been primarily used for their blast, rather than for their fragmentation, characteristics. This work reports on an investigation, using a flash X‐ray imaging technique, of the ability of TBXs to shatter metal casings and to propel the resulting fragments. Three casing materials were used, AISI 1026 steel, ductile iron, and grey cast iron, while two different TBX compositions were used, with C4 serving as a benchmark. The fracture behavior of the casings, as a function of explosive fill and material characteristics, was as expected. One TBX formulation exhibited a run distance to detonation. The Gurney equation was used to correlate and compare the final fragment velocities. It was found that a larger fraction of the explosive energy was available to propel fragments in these two TBX compositions than a comparable amount of C4. This fraction of energy was influenced by the confinement of the detonation products and the ignition delay of the metal powders. These two factors had a greater influence on the fragment velocities than did material characteristics.