Topology-bundary optimization of coupled structural-acoustic systems

A new topology optimization technique is presented in this paper for optimal design of coupled structural-acoustic system with a current focus on interior noise reduction of automotive vehicles. The new tcpology optimization technique is based on an earlier published work on the analysis and sensitivity analysis of the coupled structural-acoustic system [1-2]. It is extended in this paper to consider the optimum material distribution in the structural domain as well as the optimum boundary shape between the structural and acoustic domains for the purpose of interior noise reduction. Firstly, a fixed boundary problem was considered with a focus on the material distribution in the structural domain to achieve the desired acoustic response inside the acoustic domain. The general formulation developed accounts for the full coupling effect of the structural vibration and acoustic pressure and can consider multiple (structural and acoustic) inputs and outputs over a predefined frequency domain. Secondly, optimization of the boundary shape between the structural domain and acoustic domain is considered with a focus on modifying acoustic resonant modes as well as the interaction between the structure and acoustic field. Finally, optimal material distribution and boundary determination are simultaneously considered to obtain a truly optimum structural-acoustic system for the desired performance requirements of the coupled system. Examples will be given to demonstrate the feasibility and effectiveness of the new topology optimization technique for various applications.