近年來隨著工業的高度發展，人們越來越關注噪音問題，噪音除了使人們感到不適，高分貝的音量更是會損害聽力造成永久性傷害。然而，低頻噪音(<500Hz)由於較長的波長，難以利用泡棉、纖維等傳統多孔性吸音材料進行聲音吸收。因此在此研究中，將針對低頻聲音進行共振吸音結構設計，目標在低頻有全吸收的效果並拓寬其吸收頻寬，利用理論預測並控制其聲音吸收頻段。
本文提出內含雙螺旋聲學共振器之吸音材料，依據阻抗理論設計結構幾何，進行結構最佳化，使最大吸收率的頻段發生在預期區域。搭配有限元素模擬軟體 COMSOL Multiphysics 驗證理論吸收率的正確性，並觀察共振腔能量損耗、聲壓場與粒子速度場。最後以三維列印技術製作實驗樣本，在 ISO-10534-2 規範下使用阻抗管系統量測樣本聲音吸收率，交互比對理論、模擬及實驗結果。理論結果顯示此材料可在最低309Hz達到聲音全吸收，並有吸收頻寬20Hz (聲音吸收率 > 0.5)，且其樣本厚度與波長比率可小至1.08%。除了單層雙螺旋聲學共振器之外，本文也延伸研究雙層共振器的設計，藉以拓寬低頻吸收頻寬。

In recent years, with the rapid development of industry, people have been paying more and more attention to noise control. In addition to making people feel uncomfortable, high-decibel noise causes permanent hearing damage. Low-frequency noise (< 500 Hz) is difficult to absorb with traditional porous sound-absorbing materials, such as foam and fibers. Therefore, in this study, we design an alternative absorbing structure for alleviating low-frequency sound. The goal is to achieve total absorption at low frequency, broaden absorption bandwidth, and manipulate sound absorption band.
In this thesis, Double-spiral resonator (DSR) is proposed. By using the acoustic impedance theory, the structural geometry is designed for attaining that the maximum sound absorption in the frequency range of interest. With the finite element simulation software COMSOL Multiphysics, the theoretical absorption coefficient of the models is verified, and the acoustic pressure field, particle velocity field, and energy loss mechanism in the resonant cavity are examined. Finally, three-dimensional printing technology is used to fabricate test specimens, and the impedance tube system is employed to measure the sound absorption coefficient under the ISO-10534-2 standard. Theoretical results show that the DSR can achieve total sound absorption at 309 Hz and create an absorption bandwidth of 20 Hz (sound absorption coefficient > 0.5), and a thickness-to-wavelength ratio is about 1.08%. In addition to the single-layer structure, the further designs of the Two-layer resonators are also proposed.

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