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標題: | 利用四分之一波長共振腔的聲學超材料來抑制噪音之研究 Noise Suppression with Acoustic Metamaterials Based on Quarter-Wave Resonators |
作者: | 萬祐安 You-An Wan |
指導教授: | 邱奕鵬 Yih-Peng Chiou |
關鍵字: | 光柵反射器,四分之一波長共振腔,品質因子,穿透損失, Grating reflector,Quarter-wave resonator,Quality factor,Transmission loss, |
出版年 : | 2022 |
學位: | 碩士 |
摘要: | 本研究重點在於利用共振腔的特性去設計反射器,達到抑制特定聲音波段噪音之效果。我們設計出聲波光柵反射器、三種不同維度的大型腔體共振腔,與聲學領域中在做隔音的處理方式相比,我們並不需要完整固體的反射面或吸收面做為隔音或吸音的試件,就算是反射表面充滿了孔洞,且孔洞面積甚至大於一半,利用側向耦合(side coupling)的模式,在共振頻段會有極大反射和吸音的現象,也能達到隔音效果。
此外本論文打算以空腔體共振腔做為反射器,將聲波能量束縛在空氣之中,由於聲波是純量,不同於電磁波領域的是橫向電場E(z)、H(z),聲波可以建構出的三種維度共振腔:一維的長管型大型共振腔、二維的圓柱型大共振腔、三維則是使用富勒烯(巴克球)類週期結構,構成球型共振腔。 無限週期性聲波光柵反射器可視為無限大吸音陣列,為了實現吸音陣列的抑制噪音之實驗,本論文先從反射器的反射率、穿透率和穿透損失進行分析,並且考慮到現實環境中可能出現的誤差,使用數值軟體進行模擬,取得最佳的四分之一波長吸音陣列之參數。本研究對於不同尺寸的陣列進行實驗,並對數據做分析,最終設計出長160 cm、寬135 cm的大型吸音陣列,在共振頻率785 Hz,其穿透損失為10 dB,頻寬為 65 Hz。 The focus of this study is to use the characteristics of the resonator to design the reflector to achieve the effect of suppressing noise in a specific bandwidth. We design an acoustic grating reflector, with three different dimensions of a large cavity resonator, compared with the acoustic field in the sound insulation processing, we don’t need a complete reflective or absorption surface to cover sound insulation or sound-absorbing sample. Even if the surface of reflection is full of holes, and the hole area is even greater than half of total area, we can still use the principle of side coupling to achieve reflection and effect of sound absorption. In addition, we intend to use cavity resonator as a reflector to confine the energy in the air. Because the sound pressure is scalar, unlike the electromagnetic field is transverse electric fields E ⃗(z) and H ⃗(z), it can construct three kinds of cavity resonator. The first one is one dimensional long tube resonator; then the second type is two-dimensional cylindrical resonator, and the third is fullerene (buckyball) periodic-like structure, achieving the thee-dimensional spherical resonator. An infinite periodic acoustic grating reflector can be regarded as an endless acoustic absorption array. In order to construct the experiments of absorption array, we will start from the characteristics of reflectance, transmittance and transmission loss. Also, we simulated the probably inaccuracy of experimental structure in reality to explain the errors in experiment by using numerical simulation software. And finally, we obtain the best parameters of quarter-wavelength sound absorption array. Based on the experimental analysis of different sizes of array, and finally, a large sound-absorbing array of 160 cm long and 135 cm wide was designed, with a resonant frequency of 785 Hz and a transmission loss of 10 dB with a bandwidth of 65 Hz. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/89665 |
DOI: | 10.6342/NTU202203760 |
全文授權: | 未授權 |
顯示於系所單位: | 光電工程學研究所 |
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