Sound Absorption by Acoustic Microlattice with Optimized Pore Configuration

TL;DR

This paper establishes a fundamental relation linking pore size, boundary layer thickness, and sound absorption efficiency, validated through microlattice materials with optimized pore configurations.

Contribution

It introduces a universal relation for optimizing sound absorption by tuning pore size relative to the viscous boundary layer, guiding material design.

Findings

Optimal sound absorption occurs when pore size is twice the viscous boundary layer thickness.

Validated microlattice structures demonstrate tunable sound absorption.

Guidelines for pore size and porosity optimization are provided.

Abstract

Sound absorption or dissipation principally involves joint interactions between sound waves, material morphology and the air medium. How these elements work most efficiently for sound absorption remains elusive to date. In this paper, we suggest a fundamental relation concisely cross-linking the three elements, which reveals that optimal sound absorption efficiency occurs when the pore size of the material is twice the thickness of the viscous boundary layer of the acoustic air medium. The study is validated by microlattice materials comprising of well-controlled regular structures that absorb sound in a tunable manner. Optimized material morphology in terms of pore size and porosity is determined to provide a robust guidance for optimizing sound absorbing materials.