Research On The Impact Coupling Behavior Of Equipment And Hull In Medial Space Of Double-Layer Underwater Vehicle

With the increasing threat of non-contact underwater explosion,the research on shock resistance of shipboard equipment has become more and more important.The inter-board equipment of submarine is usually located in the medial space of double-layer underwater vehicle,which plays an important role in ensuring the integrity of the ship’s vitality.Therefore,it is of great theoretical value and engineering significance to explore the anti-impact research methods of the inter-shipboard equipment of submarine.However,there are few studies on shock resistance of this kind equipment.Therefore,considering the similarities and differences in the impact resistance research of different inter-shipboard equipment,the dynamic theory analysis and impact simulation of two typical inter-shipboard equipment of submarine,lifting device and high-pressure air bottle base structure,are discussed,and preliminary shock protection design and improvement are carried out.The details are as follows:Firstly,a general shock dynamic model analysis method for inter-shipboard equipment was established.The attached water quality of regular structure in infinite water was theoretically discussed,and the attached water quality of equipment in finite enclosed water was solved by fluid-structure coupled modal analysis;the stiffness provided by pressure shell and enclosure plate frame is determined by stiffness calculation,and the stiffness simulation model of equipment was established;the connection method of components in equipment was studied and the applicability of various connection modes such as binding、contact constraints and bolt connection was curtained.Secondly,the characteristics of the impact environment of the submarine are analyzed comprehensively from the transmission shock wave and the transmission load of the hull.In terms of transmission load,the transmission effect of underwater explosion shock wave before and after double-sided immersion plate was studied.The calculation formula of transmission wave was deduced theoretically.In addition,the peak value、pulse width and impulse of transmission wave were verified by numerical simulation,and the calculation method of transmission shock wave load in enclosed space was determined.In the aspect of hull transfer load,the coupled acoustic-structural analysis was used to calculate the impact load transformed by hull under many conditions,and the effects of the key factors such as explosive direction、impact factor、depth and reinforcement components on the impact load are summarized.Thirdly,the applicability of current dynamic design analysis method and time domain simulation method in the study of impact resistance of inter-shipboard equipment was analyzed.Dynamic design analysis method and time domain simulation method were used respectively to calculate the impact resistance of lifting device and air bottle base structure.The shock response characteristics of equipment were analyzed,and the weak areas of the equipment were found,which provided a basis for the protection design.On this basis,the transient dynamic analysis of the two equipment were carried out within considering the transmission shock wave load,which showed that the transmission load intensity is slightly weaker than impact load transformed by hull under the same working condition.Finally,the impact protection research and improvement of the inter-shipboard equipment were carried out.For the lifting device,the influence of the parameters of the shock isolation system on the dynamic response of the lifting device was explored,and the optimal shock isolation stiffness and damping of the lifting device system are determined.The efficiencies of the single-layer and double-layer shock isolation systems were compared.For the air bottle base structure,the thickness of each part of the base was improved,the impact tests of different sizes of the base were carried out,the numerical simulation method was validated,the weak area was optimized.Besides,this paper explored the failure mechanism of the bolt fixing plate of the base and provided the general preliminary design formula of the bolt fixing plate.