Optimization techniques in structural acoustic design

Abstract

This paper addresses optimization for the minimization of total radiated acoustic power from practical three-dimensional structures. Optimization techniques currently focus on developing coupled computational models for the structural and acoustic responses, in terms of certain controllable design variables. Typically, the computational tools for developing these models are finite element and boundary element methods. For a given assumed excitation, the coupled model is optimized to produce a minimum radiated power condition. This approach is computationally intensive, due to the need to explicitly solve for the total response at each design iteration. The recently developed concept of ‘‘exterior acoustic modes’’ may provide a means to significantly reduce the computational effort required for the acoustic portion of a response model, for frequencies below some coincidence frequency criterion. The exterior modes concept yields a greatly simplified objective function for total radiated power, as compared to an objective function obtained through other means. This paper discusses the current art, and presents the alternative approach using the exterior modes representation. Optimization of the mass distribution of a baffled finite plate is used as a benchmark problem.