Simulation And Experimental Research On Acoustic Characteristics Of Underwater Composite Rudder Wing

Due to the excel ent underwater propagation performance of acoustic waves,the application of acoustic theory not only covers the civilian aspects,including fishery resources exploration,island and reef collision avoidance,but also extends to military fields such as acoustic stealth of ships.The concealment of surface and underwater ships will directly affect the safety of warships and crew.In order to achieve better concealme nt performance of military ships,it is very important and urgent to conduct acoustic research on warships and their appendages.And rudder wing is a common component of warship structure,its acoustic contribution to the ship can not be ignored,so this paper will conduct a comprehensive acoustic study on the original size model of the rudder wing.Among the many methods to improve the acoustic properties of structures,using composite materials is one of the most widely used methods recently.The application of composite material in rudder wing structure has been done.In engineering,the composite material composed of reinforced material and matrix material is usual y used to replace the original steel,so as to achieve the ideal acoustic performance.In this paper,a composite rudder wing model composed of surface glass fiber reinforced composite,interla yer polyurethane sound absorption composite,inner rigid filled foam and steel skeleton is presented,and the pure steel rudder wing is compared.By using the acoustic finite element method combined with the automatic matching layer technique,the effects of the composite materials on the acoustic performance of the rudder wing are studied from the aspects of vibration sound radiation and acoustic scattering.The specific research work is as follows:Firstly,the original model of composite material and steel of rudder wing is established.The vibration and acoustic radiation properties of the two material models are compared under two different conditions,namely,unit harmonic force excitation at skeleton junction and the center of plate lattice.In order to optimize the acoustic radiation performance of the original composite materials,a variety of sound transmission and sound absorption materials were selected to study the influence of different materials to find a better composite combination.Secondly,as for acoustic scattering,we continue to study the rudder wing model of the two materials,compare the scattering sound pressure and acoustic target strength characteristics of the two materials il uminated by the incident of unit plane wave,and study the influence of composite material on the acoustic scattering performance of rudder wing.Then,in order to optimize the acoustic scattering performance of the original composite materials,a variety of sound transmission and sound absorption materials are selected to study the influence of different materials to find a better composite combination.Thirdly,based on the experimental project,the acoustic target strength of two kinds of material rudder wing models is measured,and the experimental results of high signal-tomixing ratio are analyzed,and the reduction effect of composite rudder wing model on acoustic target strength is discussed.Finally,the experimental results are compared with the numerical solution calculated by the finite element method,which further verifies the correctness of the finite element method.