Development of Broadband Acoustic Metamaterial for Environmental Noise Control

Chai, Ming Han (2025) Development of Broadband Acoustic Metamaterial for Environmental Noise Control. Final Year Project (Bachelor), Tunku Abdul Rahman University of Management and Technology.

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Abstract

Traffic noise poses serious health risks, particularly for those living near highways or railway stations, with conventional noise barriers often failing to absorb low-frequency sound effectively. Exposure to low frequency noise especially at the range of 0.5 to 2 kHz in long term led to the risk of hearing loss. This conventional noise barrier limitation, due to the reliance on mass law and bulky materials, highlights the need for innovative solutions like acoustic metamaterials to achieve broader and more efficient noise reduction. This project aims to design a noise barrier using broadband acoustic metamaterials, analyse their absorption mechanisms and performance, and compare the results with conventional materials through ANSYS simulations. This study investigates the acoustic performance of polypropylene metamaterial structures designed with space-coiling resonators and integrated beam-like resonators. Improving design parameters such as beam-liked resonator size and pattern of space coiled resonator is done with using ANSYS acoustic module, and results were validated through mesh convergence tests. The validation result with good correlation is obtained through comparison between JCA model and Jan Sikora data. Among all the models evaluated, BLR5 and BLR1 designs demonstrated superior absorption performance, achieving good sound absorption coefficient of 0.9755 and 0.91727 at 1000 Hz and 1250 Hz, respectively. BLR7 design model with seven minimized resonators, showed effective broadband absorption within the range of 31.5 Hz to 1000 Hz. Structural features such as cap thickness, coiling depth, and resonator position were found to significantly influence acoustic behaviours. These design models could be applied on other applications including 220kV of substations, school area and others. Thus, objective is meet with the used of BLR7 design model for achieving broadband noise absorption. By comparing to existing conventional polypropylene material, this BLR7 design had improve the average overall sound absorption coefficient of 6.52% within the range of sound frequency between 31.5 Hz and 1250 Hz.