Research On Acoustic-Structure Sensitivity And Structure-Acoustic Optimization Design

Acoustic-structure sensitivity is a change rate of response acoustic pressure with respect to structure design parameters, it has the vital significant to the structure noise reduction, and it is one in the design contents of quiet structure; structure-acoustic optimization based on Acoustic-structure sensitivity may design the most superior low noise structure, and it is one of goals of structure-acoustics design. The acoustic design for vehicle, ship, plane and ordinary industry is very important to improve the carborne acoustic comfort and to enhance competitiveness for the products in market, the Acoustic-structure sensitivity and the structure-acoustic optimization can provide a ration and optimum design method for the vibration structure. The objective of this fundamental study is to develop effective ,general method for the noise reduction of vibration structure .This paper discusses the fundamental theory of FEM and BEM for structure-acoustic numerical simulation, compares advantage and disadvantage for FEM and BEM, summarizes their application in structure-acoustic simulation, debates the research history and actuality for Acoustic-structure sensitivity and structure-acoustic optimization. The acoustic-structure sensitivity formulation basing on FEM and BEM is deduced and implemented, the mathmatical model of structure-acoustic sizing design optimization is established and achieved basing on acoustic- structure sensitivity by used of the the feasible direction method.The main work in the thesis is as follows: Based on the FEM, the numerical analysis of Dynamics displacement Response, velocity Response and its Sensitivity is deduced and implemented for the plate vibration. The velocity Sensitivity of structure vibration with respect to structure parameters is essential to calculate the acoustic- structure sensitivity; The velocity sensitivity of vibration structure with respect to structure parameter, the response pressure and response acoustic power with respect to the normal velocity is carried out by using of FEM and BEM, respectively, and then these sensitivity were combined to obtain a acoustic- structure sensitivity; For purpose of minimizing structure noise, the mathematical model of the sizing design optimization for minimizing the vibrating velocity is established and performed. The acoustic radiation of structure vibration bas been studied by use of the BEM before optimization and after optimization, the results were compared for the former and the latter; Based on the FEM of the coupled acoustic-structure system, the sensitivity of eigenvalue is deduced and performed; Based on the FEM of the coupled acoustic-structure system, the acoustic response feature is deduced and performed, the modal superpose method of the acoustic-structure sensitivity is put forward and performed; Based on the FEM of the coupled acoustic-structure system, the mathematical model of the sizing design optimization for minimizing acoustic response, structure weight and the multi-object optimization is established and performed basing on acoustic-structure sensitivity by used of the feasible direction method; The acoustic transfer function simulated by a unit force is deduced and performed by used of FEM and BEM, respectively, and then acoustic response feature of the structure random vibration simulated by a...