Hetero-blast from a structural reactive material cylinder under explosive loading

Abstract

A structural reactive material (SRM) cylinder is considered here as a limiting case of a dense metallic energetic system in which a mixture of metal particles is consolidated to the theoretical maximum density excluding porosity, to possess both high energy density and mechanical strength. Dynamic fragmentation and free-field explosion of a 103 mm inner diameter SRM cylinder charge is experimentally studied, with a wall thickness varying in a range of metal-to-explosive mass ratio M/C=1.3 to 4.0. Under explosive loading, the SRM cylinder produces a designated fragment size distribution divided into two groups: fine fragments with sizes on the order of 10² μm and below, and coarse fragments with sizes on the order ranging between 10⁰-10¹ mm. Prompt detonation shock-induced reaction (DSIR) of the expanding cloud of high-concentration fine fragments supplements the energy to enhance the primary blast as it propagates, while the coarse fragments form a high-speed, high-concentration metal momentum flux crossing the fireball and blast front to contribute to the total impulse loading to a nearby structure. Rapid impact-induced reaction (IIR) of the secondary fragments from high-speed coarse SRM fragments further enhances the reflected blast loading or generates a high interior explosion pressure as fragments perforate into the structure. The above distinctive characteristics of a unique hetero-blast are coupled effectively in the near-field range.