Dynamic Fragmentation and Blast from a Reactive Material Solid

Abstract

Structural reactive material (SRM) is consolidated from a fine granular mixture of reactive materials towards the mixture theoretical maximum density with little porosity, thus bearing both high energy density and mechanical strength. A reactive hot spot concept was investigated for fine fragmentation of a SRM solid under explosive loading to augment air blast through rapid reaction of fine SRM fragments. In this concept, micro‐sized reactive materials were distributed in a fuel‐rich SRM solid, such as MoO3 particles consolidated in a particulate aluminum base in 10Al+MoO3. Intermetallic reactions of micro‐sized MoO3 and nearby Al under explosive loading created heat and gas products to form microscale hot spots that initiated local fractures leading to fine fragments of the rest of Al. The SRM solid was made of a thick‐walled cylindrical casing, containing a high explosive in a detonation pressure range of 25–34 GPa with a casing‐to‐explosive mass ratio of 1.78. Experiments in a cylindrical chamber demonstrated the presence of a large amount of fine SRM fragments, whose reaction promptly after detonation significantly enhanced the primary and near field blast wave, as compared to the results from a baseline pure Al‐cased charge, thus indicating the feasibility of the concept.

Energy Release and Fragmentation of Brittle Aluminum Reactive Material Cases

“…The impact begins after approximately 450 microseconds, and the combustion continues vigorously for several tens of milliseconds. This behavior, seen in other enclosed detonation tests of reactive material cases [12], shows that secondary impact and fragmentation on the chamber walls are important at this scale. The relative importance of wall impact is expected to vary with the chamber volume and geometry, however.…”

“…Less work has been done to examine the fragment distributions of reactive materials, which are challenging to study due to the large quantity of extremely fine debris produced and the difficulty of recovering it while suppressing combustion and further breakup [11–13]. The size distribution of fragments is particularly important for aluminum, whose ignition temperature is dependent on the particle size and external heating rate [14, 15].…”

Enhancement of explosive effect of thermobaric explosive by metal reactive material

“…The reactive materials with Zr or Al as reaction elements release energy through exothermic reaction under highspeed impact and explosion loads [1][2][3][4][5][6][7][8][9][10]. The reaction conditions and energy release characteristics of the reactive materials have been extensively studied [11][12][13][14][15].…”

“…Jose et al [5] conducted an experiment on the energy release characteristics of powdered mixed Al/Mg under the explosion, and the results showed that the reaction occurred within a sub-millisecond time. F. Zhang et al [6] believed that microscopic hot spots were generated in the reactive material under explosion load, which promoted the material to break into fine fragments, made the reaction occur within sub-millisecond time, and enhanced the explosion shock wave. J. C. Kline et al [7] found that the use of MRMC can greatly increase the total combustion energy, and thicker casing will lead to insufficient material energy release.…”

Reactive Structural Materials: Preparation and Characterization

“…Reactive Structural Materials (RSMs) are a relatively new group of materials designed to have structural strength and store energy to be released at a desired time . Their typical applications are expected in such systems as kinetic penetrators, reactive fragments, reactive bullets, reactive armor, and munition casings .…”