| It is an important research topic with engineering background to control noise in closed cavity. Because of the coupling effect between structural vibration and acoustic field, the noise control is becoming more complex. Controlling the noise needs to research the methods in particular how to reduce the noise. With the development of computer technology and numerical calculation methods, manufacturers could predict the acoustic characteristics of the products in the designing stage by the numerical methods, and put forward to the noise reduction measurements. The method can reduce the product cost, shorten the time of product development and enhance the competitiveness of these products. The numerical calculation method has became the key technology of noise control and prediction.The main research work and innovation achievements are as follows:(1) Because of the “overly-stiff” property of finite element method, the calculation results of structure-acoustic coupling system using the FEM are susceptible to the element size and the analytical frequency. According to the advantages of the finite element method and meshless method, by combining the finite element shape function with the least square interpolation shape function and radial point interpolation shape function, the model stiff of proposed approach are more right, whose shape functions have the kronecker-delta property, compatibility and high order completeness of polynomial. The two approaches whose computational complexity is not high, can obtain higher accuracy than the finite element method.(2) In order to improve the accuracy of simulation analysis of plate structural-acoustic coupling systems, the finite element-least square point interpolation method(FE-LSPIM) and the finite element-radial point interpolation method(FE-RPIM) were extended to solve the plate structural-acoustic coupling problems and a coupled FE-RPIM/FE-LSPIM method for the analysis of plate structural-acoustic coupling systems was proposed. Numerical example of a box structural-acoustic coupled model was presented, which shows that the FE-RPIM/FE-LSPIM method achieves higher accuracy as compared with Finite Element Method/Finite Element Method(FEM/FEM) and Smoothed Finite Element Method/Finite Element Method(SFEM/FEM) for the analysis of plate structural-acoustic coupling problems.(3) To improve the accuracy of simulation analysis of plate structural-acoustic coupling systems, the ideas and methods of the analysis of plate structural-acoustic coupling systems based on FE-RPIM/FE-LSPIM. The finite element-radial point interpolation method(FE-RPIM) was extended to solve the plate structural-acoustic coupling problems and a coupled FE-RPIM/FE-RPIM method for the analysis of plate structural-acoustic coupling systems was proposed. Numerical example of a box structural-acoustic coupled model was presented, which shows that the FE-RPIM/FE-RPIM method achieves higher accuracy as compared with FEM/FEM and SFEM/FEM for the analysis of plate structural-acoustic coupling problems. Thus comparing FE-RPIM/FE-RPIM and FE-RPIM/FE-LSPIM, the former can obtain higher accuracy and efficiency.A detail research for structure-acoustic coupling problems is implemented in this dissertation, which focuses on the analysis of FE-RPIM/FE-RPIM,FE-RPIM/FE-LSPIM in the coupled systems about calculation accuracy. According to sound pressure response and modal frequency results indicated that the proposed method can be applied to solving the coupling problems, and has more engineering application foreground. |
PDF Full Text Request