Research On Vibration And Acoustic Radiation Characteristics Of Underwater Vehicle Superstructure With Composite Sandwich Panel

Compared with traditional steel materials,composite sandwich panel has been widely applied in underwater vehicle structure due to its high strength-to-weight ratio,excellent acoustic performance and strong design ability.But structural radiation noise,as an important index for measuring the combat effectiveness and vitality of underwater vehicles,is the main target of all kinds of acoustic detection weapons,and the main factor of disturbing active sonar work.For the complex structure such as underwater vehicle,the underwater vibration and acoustic radiation characteristics of the superstructure with composite sandwich panel directly affect the acoustic performance of the underwater vehicle and the comfort of the personnel.Therefore,the research on vibration and acoustic radiation characteristics of underwater vehicle superstructure with composite sandwich panel has important theoretical value and engineering background.This paper selected vibration and acoustic radiation characteristics of superstructure with composite sandwich panel as the target,followed the combination ideas of theoretical analysis and engineering application,and carried out the analysis of vibration and acoustic radiation characteristics of underwater vehicle superstructure with composite sandwich panel.Firstly,the calculation and analysis method of mechanical properties on composite sandwich panel is discussed,which is suitable for shear deformation theory.Through the theoretical analysis and example verification,the method of finite element modeling of composite sandwich panel is determined,and the stratified modeling method with shell element is used to establish the numerical analysis model of composite sandwich panel.Then,based on the coupled acoustic-structural finite element analysis technique,this paper has completed the analysis of underwater radiation noise of structures,carried out the underwater noise test of stiffened cylindrical shell,and verified the effectiveness of coupled acoustic-structural finite element method,which established theoretical foundation for the research of vibration and acoustic radiation characteristics of underwater vehicle superstructure with composite sandwich panel.Depended on the stratified modeling technology with composite sandwich panel,combined with the requirement of structural grid partition and the truncation technology of flow field in infinite domain,and completed the establishment of the numerical analysis model of superstructure with composite sandwich panel.Based on the coupled acoustic-structural finite element analysis method,the vibration and acoustic radiation characteristics of steel material,acoustic material and composite sandwich panel with superstructure shell plate are compared and analyzed from three aspects: vibration characteristics in the air,underwater vibration characteristics and underwater radiation noise characteristics.It is found that the composite sandwich panel of superstructure is beneficial to improve the acoustic radiation performance of the underwater vehicle.On the basis of the above results,this paper continued to use the coupled acoustic-structural finite element analysis method,by changing the thickness of shell,the thickness of connecting structure,reinforcement and other common structural parameters,explored the change rules of underwater vibration and acoustic radiation characteristics of superstructure with composite sandwich panel.At the same time,it can guide the proposal and selection of composite superstructure structure acoustic optimization scheme,complete the optimization design of underwater vibration and acoustic radiation characteristics of superstructure with composite sandwich panel,and provide reference for theoretical research and engineering application of underwater vehicle superstructure composite sandwich panel.Finally,this paper researched on the problem of bolt connection between shell plate of superstructure and the cabin,the bolt connection mode is simulated by the beam element and the constraint of MPC,and combined with the engineering practice of bolt loosening and other issues.Studied on the influence of bolt size,bolt spacing and other parameters on underwater vibration and acoustic radiation characteristics of superstructure with composite sandwich panel,and it can provide the new idea for solving practical engineering problems.In this paper,the validity of the coupled acoustic-structural finite element analysis method is verified by means of theoretical analysis,numerical calculation and model test.Then,the model of composite sandwich panel is built by hierarchical modeling method with shell element,and the vibration and acoustic radiation characteristics of underwater vehicle superstructure with composite sandwich panel are calculated and analyzed.This paper explored the change rules of underwater vibration and acoustic radiation characteristics of superstructure with composite sandwich panel by changing the thickness of shell,the thickness of connecting structure,reinforcement and other common structural parameters,and guided the design and selection of composite superstructure structure acoustic optimization scheme.And it also discussed the influence of vibration and acoustic radiation characteristics of underwater vehicle superstructure with composite sandwich panel on parameters of bolt connection,provided reference for theoretical research and engineering application of underwater vehicle superstructure composite sandwich panel.