Shaped Charge Jet Initiation Tests with Covered High Explosive Charges with Air Gaps.pdf

Shaped Charge Jet Initiation Tests with Covered High ExplosiveCharges with Air GapsManfred Held*TDW-Gesellschaft fu¨r verteidigungstechnische Wirksysteme mbH, 86523 Schrobenhausen (Germany)SummaryTests have been carried out with 5mmthick plastic discs introducedin a 10mm large air gap in split high explosive charges. If the secondcharge has a 5mm air gap behind the 5 mm polyethylene disc arelatively prompt initiation is given. If the air gap behind the 5 mmplastic disc is only mm an initiation occurs only in the forwarddirection which starts with a large build-up distance and a long startingdelay time without any retonation. Finally with direct contact of the5 mmthick plastic disc to the second charge no detonation starts in thegiven geometry. These tests do not con?rm the initiation theory toavoid impacts of powdered high explosive charge particles which cancause the initiation of the second charge. The reason could be theearlier discussed desensitization by the pression of the bulgingcover material into the high explosive . IntroductionChick and Hatt(1)found that the high explosive charges aremore easily initiated if the charge is arranged with an air gapbehind a barrier. This effect was con?rmed by the authorwith a very similar test setup(2). Haskins(3)reported XDT-initiations where uncon?ned explosives reacted after bulletor fragment impacts, when the powdered