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Experimental investigation of an acoustic metamamaterial barrier design composedof a square prism within a hexagon recess


Citation

Mu, Luo and Zulkefli, Zamir Aimaduddin and Abdul Jalil, Nawal Aswan and Putra, Azma and Othman, Muhammad Nur and Raja Ahmad, Raja Mohd Kamil (2021) Experimental investigation of an acoustic metamamaterial barrier design composedof a square prism within a hexagon recess. ASEAN Engineering Journal, 11 (3). 57 - 70. ISSN 2229-127X

Abstract

This paper presents an experimental investigation of an acoustic barrier composed out of an acoustic metamaterial unit cell. The design of the unit cell consists of a square prism, acting as a resonator, within a hexagonal recess manufactured out of a single material. Two materials were used to manufacture the unit cell: PolyMide Polycarbonate and Polylite Polylactic Acid. The acoustic performance of the unit cell was quantified for both materials using the acoustic absorption coefficient and acoustic transmission loss values for frequencies between 100 Hz and 5,000Hz. The experimental results indicate that the design reduced the peak absorption coefficient for both materials while also introducing two additional peaks at around 1,500 Hz and at 4,000 Hz. Changes to the absorption coefficient values were observed for frequencies above 1,000 Hz while minimal changes were observed for frequencies below 1,000 Hz. These results indicate that the proposed design, is able to widen the effective frequency band, or stop band for acoustic absorption for frequencies above 1,000 Hz compared to the absorption coefficient of the material. The experimental results also indicate that the design increases the peak transmission loss by about 7 dB at 4,000 Hz. For sounds below 3,000 Hz, the design will only change the transmission loss by about 3 dB for frequencies between 100 Hz to 3,000 Hz. These results indicate that the acoustic metamaterial design, consisting of resonator in a recess manufactured out of a single material, is able to broaden the effective frequency range for sound absorption for frequencies between 1,000 Hz and 4,000 Hz and at increasing the transmission loss values for frequencies between 3,000 Hz and 5,000 Hz. It can be concluded that the resonator in recess metamaterial design, manufactured out of a single material, can be used to increase the stop band for acoustic absorption for frequencies above 1,000 Hz and to increase the transmission loss for frequencies above 3,000 Hz.


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Official URL or Download Paper: https://journals.utm.my/aej/article/view/16872

Additional Metadata

Item Type: Article
Divisions: Faculty of Engineering
DOI Number: https://doi.org/10.11113/aej.v11.16872
Publisher: ASEAN University Network/Southeast Asia Engineering Education Development Network
Keywords: Acoustic barrier design; Acoustic metamaterial; Noise control
Depositing User: Ms. Nuraida Ibrahim
Date Deposited: 13 Sep 2022 04:45
Last Modified: 13 Sep 2022 04:45
Altmetrics: http://www.altmetric.com/details.php?domain=psasir.upm.edu.my&doi=10.11113/aej.v11.16872
URI: http://psasir.upm.edu.my/id/eprint/97201
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