Damage mechanisms of full-scale ship under near-field underwater explosion

The near-field underwater explosion produced by the torpedo and other weapons was one of the most critical threats to naval ships. However, most underwater explosion tests were scale models, which would bring dissimilarities between the gravity and strain rate. We carried out a near-field underwater explosion test on a full-scale ship and recorded the dynamic response processes to make up for this shortcoming. The ship damage was mainly embodied in the loss of overall strength and damage of local structures. The Coupled Eulerian- Lagrangian (CEL) method was used to establish the model of the near-field underwater explosion, and the effectiveness of the calculation method was validated. Based on the analysis results, the near-field underwater explosion could be divided into three stages: shock wave and after flow, bubble pulsation, and water jet. The overall strength of the ship was lost under the combined action of these three stages. The "negative pressure"caused by bubble pulsation was the key to the sagging deformation of the ship. This study would guide the production of underwater weapons and ship protection design.