Multi-resonant scatterers in Sonic Crystals: Locally Multi-resonant Acoustic Metamaterial

TL;DR

This paper introduces a locally multi-resonant acoustic metamaterial made of 2D periodic scatterers that exhibit multiple low-frequency attenuation peaks, enabling the design of effective sonic barriers.

Contribution

It presents a novel design of a 2D multi-resonant acoustic metamaterial with tunable low-frequency attenuation properties based on elastic and cavity resonances.

Findings

Multiple attenuation peaks in low-frequency range

Strong dispersive effective properties at subwavelength scale

Potential for designing wide-band acoustic barriers

Abstract

An acoustic metamaterial made of a two-dimensional (2D) periodic array of multi-resonant acoustic scatterers is analysed in this paper. The building blocks consist of a combination of elastic beams of Low-Density Polyethylene Foam (LDPF) with cavities of known volume. Sound inside the structure can excite elastic resonances of the material as well as acoustic resonances in the cavities producing several attenuation peaks in the low-frequency range. Due to this behaviour at the subwavelength regime we can define this periodic array as a Locally Multi-Resonant Acoustic Metamaterial (LMRAM) presenting strong dispersive characteristics of the effective properties with subwavelength multi-resonant structural units. The results shown in this paper could be use to design effective Sonic Crystal Acoustic Barriers with wide tunable attenuation bands in the low-frequency range.