Wide tailorability of sound absorption using acoustic metamaterials

TL;DR

This paper demonstrates how acoustic metamaterials with resonant cavities can be engineered to achieve broadband, tailorable sound absorption without dissipative materials, offering promising applications in soundproofing.

Contribution

It introduces a novel approach using deep subwavelength resonators to control sound absorption across a wide frequency range.

Findings

High confinement of acoustic energy in resonators enhances absorption.

Filling ratio critically influences absorption properties.

Experimental results confirm broadband, tailorable soundproofing potential.

Abstract

We present an experimental demonstration of sound absorption tailorability, using acoustic metamaterials made of resonant cavities that does not rely on any dissipative material. As confirmed by numerical calculation, we particularly show that using quarter-wave-like resonators made of deep subwavelength slits allows a high confinement of the acoustic energy of an incident wave. This leads to enhance the dissipation in the cavities and, consequently, generates strong sound absorption, even over a wide frequency band. We finally demonstrate experimentally the key role of the filling ratio in tailoring such an absorption, using a metamaterial constituted of space-coiled cavities embedded in a polystyrene matrix. This paves the way for tremendous opportunities in soundproofing because of its low density, low volume, broadband and tailorable capabilities.