Computational design of locally resonant acoustic metamaterials

TL;DR

This paper presents a computational framework for designing lightweight acoustic metamaterials with tailored bandgaps for noise insulation, combining multiscale homogenization, model reduction, and topology optimization.

Contribution

It introduces a novel design procedure integrating multiple computational tools to optimize locally resonant acoustic metamaterials for specific frequency attenuation.

Findings

Designs effectively attenuate targeted sound frequencies.

Viscoelastic coatings influence overall acoustic performance.

Computational approach enables tailored metamaterial properties.

Abstract

The so-called Locally Resonant Acoustic Metamaterials (LRAM) are considered for the design of specifically engineered devices capable of stopping waves from propagating in certain frequency regions (bandgaps), this making them applicable for acoustic insulation purposes. This fact has inspired the design of a new kind of lightweight acoustic insulation panels with the ability to attenuate noise sources in the low frequency range (below 5000 Hz) without requiring thick pieces of very dense materials. A design procedure based on different computational mechanics tools, namely, (1) a multiscale homogenization framework, (2) model order reduction strategies and (3) topological optimization procedures, is proposed. It aims at attenuating sound waves through the panel for a target set of resonance frequencies as well as maximizing the associated bandgaps. The resulting design's performance is later studied by introducing viscoelastic properties in the coating phase, in order to both analyse their effects on the overall design and account for more realistic behaviour. The study displays the emerging field of Computational Material Design (CMD) as a computational mechanics area with enormous potential for the design of metamaterial-based industrial acoustic parts.