Work

Viscoelastic structural damping enables broadband low-frequency sound absorption

Year: 2025

Type: article

Abstract: Low-frequency sound absorption has traditionally relied on air-resonant structures, such as Helmholtz resonators, which are made of stiff materials that undergo negligible deformation. In these systems, energy dissipation arises primarily from air motion and thermal-viscous effects, resulting in inherently narrowband performance and bulky, complex designs for broadband absorption. Here, we presented a composite acoustic metamaterial that replaces the high-stiffness neck of a Helmholtz resonator with a soft, viscoelastic cylindrical shell. This structural modification enables material deformation and shifts the dominant energy dissipation mechanism from air resonance to intrinsic viscoelastic damping. A single unit achieves over 97% absorption across a broad low-frequency range (227 to 329 Hz) with deep-subwavelength thickness (λ/15 at 227 Hz). We developed a discretized impedance model that quantitatively links material properties and geometry to absorption behavior. Our results established a materials-centered design paradigm in which both material selection and geometry serve as coequal, tunable parameters for compact, broadband low-frequency sound control.

Source: Proceedings of the National Academy of Sciences

DOI: 10.1073/pnas.2520808122

Authors: Yanlin Zhang, Junyin Li, Qiongying Wu, Marco Amabili, Diego Misseroni, Hanqing Jiang

Institutions: Westlake University, Zhejiang University, University of Trento

Language: English

Topic: Acoustic Wave Phenomena Research

Subfield: Biomedical Engineering

Field: Engineering

Domain: Physical Sciences

Open Access status: hybrid

Funders: European Resuscitation Council, Westlake University, European Commission, National Natural Science Foundation of China

Awards: G1354141024, G4858462498, G5660170224