Sound attenuation of a periodic array of micro perforated ducts and panels

Abstract

Phononic crystals and metamaterials are commonly classified as engineered materials that havespecial properties that are not found in natural materials. They have received increasing attention from researchers in recent years. In the case of acoustic metamaterials with periodicarrangements, the exhibition of frequency bands where the wave propagation is predominantlynon-propagating (band gaps) shows remarkable potential in several applications, such as vibration isolation, acoustic cloaking, acoustic lenses and others. Micro-perforated duct or panel are acoustic filters composed by a thin tube or plate across whose surface are distributed holes of sub-millimetric size, respectively. They provides high acoustic resistance and low mass reactance due to the size of its holes in which they promote the dissipation of the acoustic energy of the incident sound wave. In this work, it is intended to use this devices arranged as a metamaterial, i.e. using periodicity and/or local resonance, in order to produces large frequency band gaps that will improves its capacity to attenuates the sound. Therefore, the present research project aims to study such acoustic metamaterial in order to develop analytical and numerical design tolls with experimental verification. In addition, it is also the aim to optimize this metamaterial in order to maximize its sound attenuation performance. (AU)