Mitigation of the quasi-static pressure in confined explosions using a surrounding material

Surrounding a charge with materials has long been known to alter the blast loading characteristics of the explosion, but the processes involved are not well understood, especially in comparison to the detonation of bare charges. The material’s inertial, thermal, mechanical and chemical response influence the blast wave formation and ultimately the output and damage. Identifying the complex mechanisms involved in detonating explosives surrounded by a medium, other than air, is key to understanding their effects and to control the subsequent blast shock and ejecta. Thermal management of the explosive energy output by rapid heat dissipation can greatly dampen the quasi-static pressure (QSP) and combustion of confined events.

High Explosive (HE) tests have been conducted in a confined environment to analyse the mitigation effectiveness of a selection of materials through analysis of the QSP development. A 275-litre unvented chamber instrumented with pressure transducers mounted in the wall was subjected to spherical PE10 charge detonations. Bare and water-mitigated charges are used as a baseline to qualify the effectuality of a range of dry, wet and saturated materials, including vermiculite, perlite and silica. This paper presents the initial findings of the test series and lays out the subsequent testing in the High Explosive Advanced Diagnostics and Media Modelling (HEADaMM) programme.