Analysis Of Structural Vibration And Acoustic Radiation Based On MATLAB

In recent years, engineering structural acoustic radiation has attracted more and more attentions of scholars.It exists widely in different fields,such as shipping, aero-space,rail transportation,petroleum chemical industry,submarines,ocean and many others.Structural acoustic radiation can be described that,as structure vibrates in ex-ternal dynamic excitations,the fluid around the structure will vibrate and then acou-stic field will be generated.Acoustic field acts on structure surface in the form of loads,futhermore,the dynamic characteristics of structure can be changed.For this reason,a structure-acoustic field coupled system is formed.As a result that vibration mode and acoustic radiation efficiency are coupled,the analytical solution of acoustic radiation is nearly impossible. With the rapid development of computer technology numerical method,the solution of complicated acoustic radiation can be achieved. 20th century, many numerical methods appear to solve partial differential equation, such as FDM,FEM,BEM.The FEM and BEM have been widely used in the fields of acoustic radiation calculation.In this paper,the calculation of acoustic radiated and the vibrating of structures is based on FEM and BEM,and fluid-solid couped effect is ignored.Finite element analysis for the vibration of structures and boundary element analysis for acoustic radiation are both achieved by the wrote program in MATLAB.The content of research as follows(1) A brief review that the FEM of structural vibration,the boundary integral formulation and BEM of acoustic radiation for three-dimensional is made.Based on previous literature,the method of applying discontinuous element to discrete acoustic boundary integral equation is put forward.In order to demonstrate the robustness and accuracy of the proposed method,two numerical examples of acoustic radiation from a pulsating sphere and cube are presented respectively,based on discontinuous BEM ,the acoustic quantity such as acoustic pressure,acoustic power,acoustic radiation efficiency, acoustic radiation modes are efficiency calculated.The acoustic radiation programs for pulsating sphere and a cube are written in MATLABlanguage.(2) The theories of FEM in vibration of structure,the boundary integral formulation and BEM of acoustic radiation for two-dimensional are reviewed briefly. Two numerical examples of acoustic radiation from a pulsating circle hole and a rocking hole are presented respectively, acoustic pressure is calculated.The results have verified the efficiency and adaptability of the proposed method.Then, based on above analysis,the FEM and BEM are used to solve for the vibration and acoustic radiation of a flat panel.(3) To the vibration of the equal thickness plate, the generalized displacement boundary conditions are given.The vibration and acoustic radiation of thin plate are discussed in detail. The programs for solve the vabration and acoustic radiation of thin plate in various boundary conditions are written with MATLAB.(4) To the stiffened plates,the vibration was simulated with finite element method through node superparametric shell element and 3 node space beam element ,the static and dynamic finite element analysis program are written by MATLAB. The feasibility of this anslysis program is tested with a specific example.Influence of various factors characteristic on performance of the acoustic radiation stiffened plates has been researched.(5) Based on the superparametric shell element,the wrote matlab software is compiled to investigate the vibration characteristic and acoustic radiation properties of the plate with changed thickness.(6) Based on the BEM and FEM theory about the three-dimensional structure ,the simulation for the process of vibration and acoustic radiation are performed by MATLAB.