Blast loading of underwater targets - A study through Explosion Bulge Test experiments

Contemporary nuclear submarines are built with double hulls which enhance the protection against explosive attacks. As the two hulls are separated by a distance (stand off), blast loading on the inner hull diminishes significantly. Thus, warheads fitted to underwater weapons with limited quantity of explosive become ineffective. In the present study, an attempt is made to quantify the enhanced protection to the underwater vessels due to double hull construction, through Explosion Bulge Test (EBT) experiments. Four different cases of air back up, water back up, partial water back up and free flood water back up are studied in the EBTs. The extent of reduction in damage to the double hulled vessel under various modes of back up are studied and discussed in this paper. Through these experiments, it is established that there is a significant reduction in damage from 22.5 to 63% to the hull when compared to air back up depending on different test conditions of water back up. The response of double hull to proximity explosion with air and water back up is simulated using a Finite Element (FE) model and compared. (C) 2014 Elsevier Ltd. All rights reserved.