Research On Experimental Scheme Of The Global And Local Strength Of Warship Subjected To Underwater Explosion

Different experimental schemes are brought up on the purpose of evaluating the longitudinal strength of the ship and the local structural strength of ship cabin, based on the feasibility, controllability and economy of the engineering application, and the practical problems are studied in detail encountered in the experimental schemes. The aim of the study is to predict the longitudinal and the local strength of the real structures through the test models within the engineering precision range on the premise of the smooth implementation of the experiment scheme and the experimental cost-effective.Firstly, the similarity law is summarized on the first shock wave and the bubble pulsation of underwater explosion in the free field, and it is studied to accurately predict the longitudinal strength of the real ship through distortion model in underwater explosion experiments of the large scale model.Secondly, the whole ship scale model experimental schematic design. The validity of the finite element model is verified by comparing the wet modes of the test and of the wet modal analysis through Acoustic-Structure Coupling Method. Suitable scaled ratio is chosen by comprehensively considering over the related factors after numerical simulation of four scale model experiment schemes of the warship. Then a distortion model can be created by carrying out a series of change on the plate and the girders to the scale model to avoid the manufacture difficulty and the forecast deviation is analyzed. An economic distortion model is chosen to form experiment scheme when the prediction deviation of the section moment is within the engineering precision range.Thirdly, real scale cabin model determination. Determine the dangerous member by calculating the simplified model of the emphasis check part of the typical cabin. Then determinate the range of the cabin model by the computation of the simplified model of the dangerous member. The computation results show:the longitudinal girder between 3m and 10.5m endure little restraintion from longitudinal girder in the range of x<3m and x>10.5m, which is also verified by the numerical calculation. The height and width of the real scale cabin model is chosen after comprehensively considering the relevant factors.Fourthly, ballast schematic designing. Adjust the natural frequency of the test cabin model through ballast and then adjust the float state to get an ideal float state and the ballast scheme. The numerical calculation of the test cabin model under design conditon is carried out and the results are analyzed and compared with the results of the whole ship.Fifthly, material-replacing scheme study. Study the error caused by replacing the material of partial structure with low-cost steel through numerical method. Then decide the kind of the low-cost steel adopted taking into count the manufacturing cost and material cost to form material-replacing scheme.