Numerical investigation of the dynamic response of a simplified floating structure subjected to two underwater explosion bubbles.

The interaction of the two coupling bubble with a floating structure is modelled to investigate the dynamic behavior of the warship under an underwater explosion (UNDEX) by coupled Eulerian-Lagrangian (CEL) method. In this study, the CEL method is first verified by the experimental results for free field underwater explosion. Then, a series of cases for various initial distance and delay intervals between the bubble pair are implemented to analyze the deformation and damage modes of the floating structure. It is observed that for large initial distance between the bubble pair synchronously generated, the floating structure can be damaged with longitudinal bending buckling in the middle domain. When the initial distance between the bubble pair decreases to a critical value, the floating structrure is damaged with a remarkable crevasse besides the longitudinal bending buckling in the middle domain. However, under two bubbles with different phase differences, the floating structure a the deformation of the whipping motion without remarkable local structural damage. This is because there is the conspicuous despression effect between two out-of-phase bubbles, which weakens the bubble pulsation load. These phenomena present a theoretical reference for further studies on the destruction of underwater explosion on the ship structure caused by multiple bubbles generated with various phase differences. [ABSTRACT FROM AUTHOR]