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標題: | 壓電薄板複合薄膜聲振研究之最佳化設計 Optimal Design of Sound Quality on Piezoelectric Plates Composite with Membrane by Vibroacoustic Analysis |
作者: | 黃御宸 Yu-Chen Huang |
指導教授: | 黃育熙 Yu-Hsi Huang |
關鍵字: | 壓電平板,疊加法,薄膜,無網格法,基本解法,聲學元件,聲固耦合分析,田口法最佳化, piezoelectric plate,uperposition method,membrane,meshless method,method of fundamental solutions,acoustic element,vibroacoustic analysis,Taguchi method, |
出版年 : | 2022 |
學位: | 碩士 |
摘要: | 本研究利用壓電薄板複合薄膜作為耳機的新型驅動元件,透過理論解析結合無網格基本解數值方法、有限元素法數值模擬與實驗量測,探討壓電陶瓷薄板複合薄膜的面外振動、聲學特性。首先討論壓電薄板於自由邊界條件下的振動特性,接者探討具有特定張於固定邊界條件下的薄膜振動特性,最後以壓電陶瓷薄板於類自由邊界條件與薄膜複合之結構,探討串聯型壓電雙層矩形陶瓷薄板複合矩形薄膜元件之結構振動與聲學特性。 實驗量測的部分使用全域式電子斑點干涉術(Electronic Speckle Pattern Interferometry, ESPI)、雷射都卜勒振動儀(Laser Doppler Vibrometer, LDV)兩種實驗技術分析面外振動特性;無響室(Anechoic Room)、人工耳(Artificial Ear)實驗則分別對自由音場與封閉音場進行聲學量測。自由音場以理論、數值模擬與實驗三種分析方法,包含利用LDV量測振動位移配合聲學理論得到對應的聲響曲線,以及使用有限元素模型於自由聲場下進行模擬,並與無響室實際量測結果進行比較,以驗證聲振耦合理論所計算的實驗結果和有限元素法的準確性。由於封閉音場的邊界條件非常複雜,因此以有限元素法與人工耳實驗兩者相互比較,以佐證模型建立方法的正確性。 綜合前述分析方法,由於實驗設計相對於模擬需耗費較大的成本,故本研究利用數值模擬分析結合田口法對聲學元件尺寸進行最佳化分析,藉由改變矩形壓電陶瓷薄板與薄膜長寬的設計變數,對聲壓曲線進行改善,並分析各變數對聲學響應之靈敏度,達到尺寸最佳化展現具有良好聲壓曲線的揚聲器設計。本研究結合理論解析、數值分析與實驗量測,並使用田口法最佳化設計於壓電陶瓷薄板複合薄膜的聲學元件設計,可以應用於新型揚聲器最佳化聲場增益特性之聲音品質的開發。 In this research, piezoelectric plate composite membrane is used as a new type of earphones. In this paper, the out-of-plane vibration and acoustic properties of piezoelectric ceramic plate composite with membrane are discussed by theoretical analysis, meshless numerical method, finite element method (FEM) and experimental measurements. The vibration characteristics of piezoelectric plates on the free boundary conditions and the vibration characteristics of membranes with specific tension on the fixed boundary are both analyzed by theoretical analysis and numerical calculation. The vibroacoustic characteristics of the piezoelectric rectangular bimorph composite with rectangular membrane is studied and is used to optimize design on earphone. Experimental measurements are used by two experimental techniques to determine the out-of-plane vibration characteristics. First, the Electronic Speckle Pattern Interferometry (ESPI) can measure the vibration mode shape and the correspondent resonant frequency. The Laser Doppler Vibrometer (LDV) can perform the single-point vibrating displacement. The anechoic room and artificial ear are used to obtain acoustic measurements. The sound quality in free field is determined by FEM and vibration experimentally measurement coupled with acoustic theory. Using the LDV to measure the vibrating displacement and substituting it into the Rayleigh’s integral to get the sound pressure level curve. The results from vibroacoustic are verified with the measurement by the anechoic chamber. Those experimental measurements are also compared with the results from FEM. In the development of earphone, the FEM model is established and modified according to the pressure-field sound measurement by artificial ear. Since the experimental design is more time-consuming and expensive, the Taguchi method is used to optimize the sound quality of the acoustic element in the study. The variable sensitivity is utilized to optimize the response of sound pressure level (SPL), and the size of loudspeaker figures out the achievement in high sound quality. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/85553 |
DOI: | 10.6342/NTU202201206 |
全文授權: | 同意授權(全球公開) |
電子全文公開日期: | 2024-06-15 |
顯示於系所單位: | 機械工程學系 |
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