Blast Wave Initiation of a Sheet Explosive Covered with Metal Plates.

Abstract

Initiationof RDX-based sheetexplosiveby a normalincident blast wavehas been studied. Explosive sheets : (i) bare (ii) aluminium foil-covered and (iii) sandwiched between different thicknesses of aluminium alloy metal plates, were impacted by the blast wave. The blast wave was produced by detonating a cylindrical plastic explosive charge kept symmetrically over the sheet at different stand-off distances in the air for varying the intensity of the blast wave. The values of critical distances, pressures obtained in the case of bare, foil-covered and aluminium alloy metal plates-covered sheet explosives have beenfitted to exponentialcurves.It is observedthat the sheet explosivesandwichedbetweenthe two metal plates having thicknesses between 4 and 12 rom requires initiating pressures higher than those for bare sheet explosives. If the sheet explosive is, however, covered by thin aluminium foil (0.25 mm) then it is initiated by blast wave of pressure lower than that for bare or sandwiched sheet explosive. Initiation of sheet explosiveby a blast waveoccurs after a delay of 2 us when it is covered with thin aluminium foil (0.25 mm) and about 7 us when it is covered with 4 mm thick aluminium plates.