A FRAMEWORK FOR MICRO-PERFORATED ABSORBERS OPTIMIZATION

The classic layout of micro-perforated absorbing devices is composed of a single homogeneous layer of micro-perforated with a backing cavity partitioned with internal septa. Some modifications of the standard layout have been introduced in the literature to improve the low-frequency performances and/or the bandwidth of such absorbers. Their effects have been typically examined separately and experimentally validated in dedicated works. In this article, we propose a design framework that uses numerical optimization to identify the best layout and its optimal constructive parameters of microperforated-based devices, with the possibility to include several enhancements of the classic design in the analysis. An analytical model is developed starting from the theory by Maa. The considered configurations' acoustic impedance and absorption spectrum are evaluated using the Transfer Matrix Method approach, easily including the effects of series and parallel arrangements of sub-units and sub-units step-wise holes cross sections. Different configurations have different design parameters, leading to optimization problems with a variable number of dimensions, which has been dealt with using a nested-optimization approach. The developed framework proved to be an effective tool for the design of enhanced micro-perforated-based devices for noise absorption.