Topology optimization of periodic structures for coupled acoustic-structure systems

Abstract

This work applies the topology optimization technique to an acoustic-structure coupled system with periodic geometry constraint in order to obtain the optimal layout of the design domain for the minimization of the pressure frequency response in the acoustic fluid. The displacement-pressure formulation (u-p) is used for the finite element analysis of the coupled system and external harmonic excitations are applied in the system. The design domain of the coupled system is considered to be composed of identical unit cells. A periodic geometry constraint is applied in the design domain considering the fluid-structure interaction and the objective function. Appling the modified bi-directional evolutionary structural optimization (BESO) technique to the system, the design domain is evolving towards the optimal topology of the unit cells through removing/adding material accordingly to the sensitivity analysis. The influence of the total number of unit cells composing the periodic structure and the aspect ratio of the unit cells are investigated in the minimization of the objective function. In order to show the capability and efficiency of the proposed formulation, two acoustic-structure systems are optimized for several cell configurations, different aspect ratios of the periodic unit cells and excitation frequencies.