Numerical Simulation Of Structural Damage Resulting From Shock Wave Of Close-in Underwater Explosion Or Contact Underwater Explosion

Underwater explosion (UNDEX) is a complex physical process of high nonlinearity. It’s able to bring great damage to a surface ship or a submarine. Far-field UNDEX mainly results in elastic response or local plastic deformation of a vessel, while close-in or contact UNDEX can cause the break or even fracture of the hull and is the largest contributor to a ship’s capsizing. Therefore, it’s very necessary to study the structural damage resulting from close-in or contact UNDEX. The main research contents of this paper are as follows:Firstly, the research achievements at home or abroad related to UNDEX are summarized from views of theory, experiment and numerical simulation, respectively. These provide the research background for the work of this paper.Secondly, the physical phenomena of UNDEX is introduced and load forms of shock wave, bubble pulse and cavitation effect are described. The Geers&Hunter model and acoustic-structural coupling method embedded in ABAQUS are elaborated. Then the Arbitrary Lagrangian-Eulerian (ALE) algorithm and its theoretical basis are introduced in great detail.Thirdly, the simulations of deformation and rupture of air-backed plates subjected to UNDEX are carried out using both acoustic-structure coupling method and ALE algorithm. Grid convergence taking structural damage into consideration is also discussed.Fourthly, finite element models of two different stiffened plates are built. One is subjected to close-in UNDEX shock and the other is subjected to contact UNDEX shock. The two cases are both simulated with acoustic-structure coupling method and ALE algorithm. All the results are compared to test results. The accuracy of acoustic-structural coupling method and ALE algorithm are examined and their advantages and disadvantages are analyzed.Fifthly, the finite element model of a full-scale surface ship is established. Using acoustic-structure coupling method, its damage evolution process is observed when subjected to close-in UNDEX shock. And three damage modes of this ship is summarized according to standoff distance.In this paper the structural damage resulting from close-in and contact UNDEX shock are validated and investigated through numerical simulation. All the results and conclusions could be reference to shock resistance design of surface ships and submarines.