Research On The Whipping Response Of Cylindrical Shell Structures Subject To Underwater Explosion Loading

As the most classic structure form of submarine, the anti-shock performance of singleand double cylindrical shell structures has always been the fundamental problemsconcerned by researchers all over the world. Since the submarine appeared the first time,abundant of studies had been implemented about varies performances and strength, andmany significant achievements are made during. However, the commencement of domesticanti-shock researches of submarine is much latter than that of the occident. Therefore, wemust exert ourselves into anti-shock researches of submarine to minish the disparitybetween us and the occident.As the slender structures’ own phenomenon subject to non-uniform loading, whippingresponse affects directly the overall strength of submarine. Therefore, dynamics ofcylindrical shell structures subject to underwater explosion is analyzed in the perspective ofwhipping response, and both methods and mechanism are discussed in this paper.As a beginning, researches on submarine shock resistance and whipping response arereviewed in the introduction. Through comparison between different methods, referencesare presented for choosing proper methods in the following parts.Accurate load input is the precondition of dynamic simulation. Combined withproceeding achievements, new method considering bubble migration effects combiningwith Geers-Hunter model is presented. Then qualitative analysis is implemented to validatethe spherical assumption of bubble pulsation model. With analysis based on potential flowtheory and boundary element numerical model, it’s proved to be reasonable since the effectof deformation movement is small quantity compared with that of the bubble pulsation, andthe effect decays a lot with the distance increasing.For the fluid-structure interaction, DAA and FEM are combined with non-shared nodesmethods. With this algorithm, data is transferred between BEM mesh and FEM mesh, whichcould provide small accuracy loss and calculation scale. Then DAA and acoustic-structure coupling methods are coupled together to solve the inner field of double cylindrical shellstructure. Good agreement is shown with the results of analytical method and other code forthe validation of numerical established above. Then numerical model established above isadopted to calculate the whipping responses of single and double cylindrical shell structures,and influence of case parameters on the whipping responses is analyzed.Finally, for the engineering application, hull-beam and Morison relative velocity modelare combined to simulate the whipping response of cylindrical shell structure. On the basisof proceeding finding, more in-depth analysis is implemented through plentiful cases, whichgives more detailed response dynamics of cylindrical shell structure whipping effect,especially for the changes of frequency components along with varies case variables. Theresearches in this paper aim to offer references for the submarine anti-shock researches andengineering calculation.