Vibration Modeling And Acoustic Vibration Characteristics Analysis Of Cavity Structure

Cavity structure cavity coupling system composed of cavity structure and internal acoustic cavity is widely used in automobile,aircraft and ship fields.Because the vibration and acoustic characteristics of the cavity structure acoustic cavity coupling system have an important impact on the normal operation of internal equipment and the acoustic environment of workers,it is of great practical significance to predict and control the vibration and acoustic characteristics of the cavity structure acoustic cavity coupling system.In this paper,the cavity structure vibration modeling and acoustic vibration coupling characteristics are analyzed,in order to provide a reliable research basis and theoretical reference for the cavity structure internal sound field distribution,acoustic vibration energy transfer law and acoustic vibration coupling mechanism.In this paper,the energy method is used to establish the theoretical models of three plate composite structure,four plate composite structure and box composite structure,and the modal and forced vibration responses are analyzed numerically.Considering the randomness of boundary conditions,the bending and in-plane vibration displacement of each plate in composite structure are described by two-dimensional improved Fourier series.In this paper,when the energy functions of different composite structures are established,the improved coupling energy is established for the structures with different coupling directions.Finally,the partial derivatives of the unknown coefficients in the structural displacement are solved by using Rayleigh Ritz method,and the characteristic equation of composite structures is obtained.The finite element method is used to solve the modal and vibration responses of different kinds of composite structures,and the results are compared with the results obtained by this method.The good comparison results show that this method is effective in solving the dynamic characteristics of composite structures.Based on the theoretical model of cavity structure,considering the structure acoustic coupling relationship between elastic structure system and acoustic cavity,the theoretical model of box structure acoustic cavity coupling system is established by using energy principle.The threedimensional improved Fourier series is used to express the sound pressure function in the acoustic cavity.Combined with Rayleigh Ritz,all the unknown coefficients in the energy function of the acoustic vibration coupling system are solved.Finally,the control equation of the closed elastic plate structure acoustic cavity coupling system is obtained.By comparing the acoustic and vibration characteristics of the structure acoustic coupling system model and the acoustic and vibration response under external excitation with the results of the finite element method,a good comparison result is obtained,which proves the effectiveness of the proposed method in predicting the acoustic and vibration characteristics of the closed elastic plate structure acoustic cavity coupling system.