A low-frequency sound absorber based on micro-slit and coiled cavity



Almeida, Gildean do N, Vergara, Erasmo F, Barbosa, Leandro R, Lenzi, Arcanjo and Birch, Robert S ORCID: 0000-0003-0861-5408
(2021) A low-frequency sound absorber based on micro-slit and coiled cavity. JOURNAL OF THE BRAZILIAN SOCIETY OF MECHANICAL SCIENCES AND ENGINEERING, 43 (3). 124-.

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Abstract

The design of a compact low-frequency acoustic absorber whose thickness is less than the operating frequency wavelength is a difficult challenge. However, recent developments in metamaterial engineering have enabled significant advances towards this goal. This paper presents an investigation of a low-frequency absorber (i.e., operating between 100 and 600 Hz) structured around a new concept of a thin cavity of coiled spaces coupled with a panel and micro-slit. The ability of this acoustic metamaterial absorber to control sound energy with increased relative bandwidth is examined analytically and numerically considering the viscous-thermal losses in both the micro-slit and coiled spaces. A prototype absorber was manufactured using advanced additive manufacturing technique and evaluated in an impedance tube apparatus. The experimental results showed the absorber capable of controlling 95% of the sound energy at 365 Hz with a relative bandwidth of 60.3%. These results compare well to those obtained from the analytical analysis and finite element method. Thus, the proposed acoustic absorber is shown to be capable of operating in the deep-subwavelength scale.

Item Type: Article
Uncontrolled Keywords: Low-frequency absorber, Coiled spaces, Acoustic metamaterial, Micro-slit, Visco-thermal effects
Depositing User: Symplectic Admin
Date Deposited: 04 Mar 2021 08:13
Last Modified: 17 Mar 2024 11:21
DOI: 10.1007/s40430-020-02763-y
Related URLs:
URI: https://livrepository.liverpool.ac.uk/id/eprint/3116452