| The aluminum alloy extrusion is composed of aluminum sheets. To improve its load-bearing and acoustic-resistance capacity, the best approach is to increase its structural stifness. In this thesis, the commercial finite element software ANSYS and Virtual. Lab Acoustic were utilized to study the structural and acoustical properties of aluminum alloy in High-speed train. The finite element of the aluminum alloy extrusion has been established to study the effects of thickness of bottom plate, excitation positions, free damping layer and the damping coefficient of structure on its mechanical and acoustical characterization. The main work can be summarized as below:(1) Based on the frequency analysis result of aluminum alloy extrusion, a cutoff frequency had been observed. When the vibration frequency is below its cutoff frequency it can be regarded as homogeneous board, or the vibration will be localized.(2) Direct finite element sound-vibration method was used to coupling analysis to explore the influence of the changes in boundary conditions, thickness of bottom plate and excitation positions on the field point acoustical pressure, acoustical radiation power and acoustical radiation efficiency. And get a better selection of the parameter settings.(3) The effect of the free damping layer on the characteristics of acoustic radiation of the aluminum plate structure was also investigated. The factors, the thickness of the free damping layer and its material properties were considered for studying the characteristics of acoustic radiation, such as point acoustical pressure, acoustical radiation power and acoustical radiation efficiency. The transmission loss of the aluminum alloy extrusion were discussed by changing the bottom palate, the damping coefficient of structure and free damping layer. It can provide reasonable technical solutions for the optimization of structure’s coupling analysis of structural vibration and sound radiation. |
PDF Full Text Request