Topology Optimization of Vibrating Bi-Material Structures with Respect to Sound Radiation

Abstract

This paper deals with topological design optimization of vibrating bi-material elastic structures of given volume, domain and boundary conditions, with the objective of minimizing the sound power radiated from the structural surfaces into a surrounding acoustic medium. The structural vibrations are excited by a time-harmonic mechanical loading with prescribed forcing frequency and amplitude, and structural damping is not considered. It is assumed that air is the acoustic medium and that a feedback coupling between the acoustic medium and the structure can be neglected. Certain conditions are assumed, where the sound power radiated from the structural surface can be estimated by using a simplified approach instead of solving the Helmholz integral equation. This implies that the computational cost of the structural-acoustical analysis can be considerably reduced. Numerical results are presented for plate and pipe-like structures with different sets of boundary conditions.