Plate-type acoustic metamaterials with integrated Helmholtz resonators
Plate-type acoustic metamaterials with integrated Helmholtz resonators
Plate-type acoustic metamaterials (PAM) consist of a thin film with periodically added masses. These metamaterials can be designed to be very lightweight and exhibit narrow bands at low frequencies with high sound transmission loss values that can exceed the corresponding mass-law considerably. In this paper, a new approach for improving the bandwidth of PAM by using Helmholtz resonators which represent the added masses is investigated. The key principle of this design is that the Helmholtz resonance gives rise to an additional peak in the transmission loss spectrum which can be tuned to increase the bandwidth of the PAM. Sound transmission loss measurements of a large-scale test sample with 270 resonators are used to demonstrate the performance of the proposed metamaterial under diffuse field excitation. Then, numerical simulations based on the finite element method are used to further investigate the physical mechanisms of the PAM with Helmholtz resonators. It is shown that when the baseplates of the Helmholtz resonators are stiff enough, the Helmholtz resonance is decoupled from the vibro-acoustics of the PAM. This can be exploited to effectively increase the bandwidth of PAM without any significant reductions of the sound transmission loss due to coupling resonances.
Acoustic metamaterial, Experiment, Helmholtz resonator, Simulation, Transmission loss
Langfeldt, Felix
2bf86877-f2cd-4c35-be0f-e38a718a915c
Khatokar, Akshay
934201e6-5eda-457e-b52c-b50e78a5db7d
Gleine, Wolfgang
6b99025f-b44a-46a8-b699-ec25962c7e75
October 2022
Langfeldt, Felix
2bf86877-f2cd-4c35-be0f-e38a718a915c
Khatokar, Akshay
934201e6-5eda-457e-b52c-b50e78a5db7d
Gleine, Wolfgang
6b99025f-b44a-46a8-b699-ec25962c7e75
Langfeldt, Felix, Khatokar, Akshay and Gleine, Wolfgang
(2022)
Plate-type acoustic metamaterials with integrated Helmholtz resonators.
Applied Acoustics, 199, [109019].
(doi:10.1016/j.apacoust.2022.109019).
Abstract
Plate-type acoustic metamaterials (PAM) consist of a thin film with periodically added masses. These metamaterials can be designed to be very lightweight and exhibit narrow bands at low frequencies with high sound transmission loss values that can exceed the corresponding mass-law considerably. In this paper, a new approach for improving the bandwidth of PAM by using Helmholtz resonators which represent the added masses is investigated. The key principle of this design is that the Helmholtz resonance gives rise to an additional peak in the transmission loss spectrum which can be tuned to increase the bandwidth of the PAM. Sound transmission loss measurements of a large-scale test sample with 270 resonators are used to demonstrate the performance of the proposed metamaterial under diffuse field excitation. Then, numerical simulations based on the finite element method are used to further investigate the physical mechanisms of the PAM with Helmholtz resonators. It is shown that when the baseplates of the Helmholtz resonators are stiff enough, the Helmholtz resonance is decoupled from the vibro-acoustics of the PAM. This can be exploited to effectively increase the bandwidth of PAM without any significant reductions of the sound transmission loss due to coupling resonances.
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APAC-D-22-00323_R1_accepted
- Accepted Manuscript
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Langfeldt et al_2022_Plate-type acoustic metamaterials with integrated Helmholtz resonators
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Accepted/In Press date: 1 September 2022
e-pub ahead of print date: 9 September 2022
Published date: October 2022
Additional Information:
Funding Information:
This work was supported by the Federal Ministry for Economic Affairs and Climate Action [Grant No. 20Q1908D].
Publisher Copyright:
© 2022 The Author(s)
Keywords:
Acoustic metamaterial, Experiment, Helmholtz resonator, Simulation, Transmission loss
Identifiers
Local EPrints ID: 470271
URI: http://eprints.soton.ac.uk/id/eprint/470271
ISSN: 0003-682X
PURE UUID: ec42f1bc-ff2d-4528-9aa6-5a77e562d688
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Date deposited: 05 Oct 2022 16:41
Last modified: 17 Mar 2024 04:11
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Contributors
Author:
Akshay Khatokar
Author:
Wolfgang Gleine
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