Computational Investigation of the Effect of Shielding in Mitigating Shock Initiation Stimuli Produced by Impact

摘要

We have conducted a study of the role of shielding in reducing the shock initiation stimulus for a simple one-dimensional representation of the problem of sympathetic detonation of munitions. We found that single layered shields made of materials with low acoustic impedance generally produce a complex shock wave structure in the acceptor. This complex structure is associated with a low level of initiation stimulus because of the breakup into several weaker shocks and the reduction of the integral of p squared with respect to t. High impedance shield materials also substantially reduce the initiation stimulus, but without the accompanying shock breakup effect. Increasing shielding thickness improves performance and can change the order of effectiveness of shield materials. With multi-layered shields composed of a high-impedance and a low-impedance material we observed shock structures depending strongly on the ordering of the materials in the shield. Multiple shock structure usually observed when the high-impedance material was the outer component of the shield and sufficient low-impedance material was present. Single compression waves with variable peak pressures and rise times were usually observed when the low-impedance material was the outer component of the shield. Substantial benefits in terms of shock breakup and the integral of p squared with respect to t reduction can be obtained by increasing the thickness of three-layered shields, which were found to perform better than five-layered shields.