A Numerical Study Of The Dynamic Responses Of Underwater Structures Subjected To Underwater Shock

Underwater explosion is a complex energy conversion process.The differences between water and air in physical properties make the explosion in these two media behave so different in physical phenomenon and loading mode.Besides these, the study of underwater explosion also involves the response of structure and the complex interaction between fluid and structure.It is difficult to obtain the analytical solution though theoretical research and mathematical model,while the accuracy of numerical simulation must be validated by compared with experimental data.Firstly, in this paper the loading and propagation mode of underwater shock are analyzed and the response of air-backed plate subjected to underwater shock is studied.By using ABAQUS, the numerical model of a plate subjected to underwater shock is set up and calculated in the same condition with experiment. The results turn out to be in good agreement with experimental data. The accuracy of simulation is validated.Based on this, some of the parameters which affect the results are analyzed to provide reference for large-scale model.Secondly, after the validation of numerical simulation method,a real underwater structure subjected to underwater shock is modeled and calculated.From the simulation result, the plots of water pressure and structural stress at different time can be given.The response of the whole structure can also be got though the analysis of the result.The analysis of cavitation proves that there will be secondary loading when the area of cavition near strurcture collapes, and it turns out that the secondary loading has a great influence on structure response which make it significant in simulation calculation and should not be ignored.Finally, underwater explosion evaluation method and "Underwater Explosion Evaluation System" are introduced.In this system,the simulation results could be used to evaluate the damage range of warship.