Broadband and intense sound transmission loss by a coupled-resonance acoustic metamaterial

TL;DR

This paper introduces a novel acoustic metamaterial that achieves broadband sound transmission loss through coupled antiresonances, surpassing 90 decibels, using a practical pillared plate structure with internal holes.

Contribution

It presents a new coupled-resonance acoustic metamaterial concept that provides broadband attenuation within a single band gap, unlike traditional narrow-band designs.

Findings

Achieves over 90 dB sound attenuation at two coupled antiresonances.

Operates effectively down to sub-kilohertz frequencies.

Uses a practical, fabricable pillared plate structure.

Abstract

The advent of acoustic metamaterials opened up a new frontier in the control of sound transmission. A key limitation, however, is that an acoustic metamaterial based on a single local resonator in the unit cell produces a restricted narrow-band attenuation peak; and when multiple local resonators are used the emerging attenuation peaks -- while numerous -- are each still narrow and separated by pass bands. Here, we present a new acoustic metamaterial concept that yields a sound transmission loss through two antiresonances -- in a single band gap -- that are fully coupled and hence provide a broadband attenuation range; this is in addition to delivering an isolation intensity that exceeds 90 decibels for both peaks. The underlying coupled resonance mechanism is realized in the form of a single-panel, single-material pillared plate structure with internal contiguous holes$-$a practical configuration that lends itself to design adjustments and optimization for a frequency range of interest, down to sub-kilohertz, and to mass fabrication.