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http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/90060
標題: | 無網格法探討跑道形薄膜複合壓電板之聲振特性 Vibroacoustic of Racetrack Diaphragm Compounded with Piezoelectric Plates Using Meshless Method |
作者: | 陳奕安 Yi-An Chen |
指導教授: | 黃育熙 Yu-Hsi Huang |
關鍵字: | 疊加法,特雷夫茨法,壓電平板,薄膜,無網格法,聲學元件,聲固耦合分析,人工耳,跑道形揚聲器, superposition method,Trefftz method,piezoelectric plate,membrane,meshless method,acoustic component,vibroacoustic,artificial ear,racetrack speaker, |
出版年 : | 2023 |
學位: | 碩士 |
摘要: | 本論文探討壓電薄板複合薄膜作為新型揚聲器的振動和聲學特性。研究方法包括理論解析、無網格特雷夫茨數值法、有限元素法和實驗量測,並進行相互對應和比較。首先對外圈固定邊界的單連通與雙連通薄膜進行振動分析,並進行張力反算;接著因壓電薄板懸吊於薄膜上形成類似自由邊界的效應,因此對壓電薄板採用自由邊界的振動理論解析;最終將壓電薄板複合薄膜形成一體結構,探討串聯型雙層壓電薄板複合跑道形薄膜元件的振動和聲學特性。
為了分析聲學元件的面外振動特性,實驗量測技術使用了全域式的電子斑點干涉術(Electronic Speckle Pattern Interferometry, ESPI)和雷射都卜勒振動儀(Laser Doppler Vibrometer, LDV),並進行了人工耳(Artificial Ear)實驗以測量封閉音場的聲學特性。數種實驗量測技術也進行聲振特性的相互比較討論,且由於封閉音場也進行了有限元素法和人工耳實驗的對應,驗證有限元素模擬的有效性。 由以上研究內容掌握壓電複合薄板的聲振特性後,考慮到實驗設計製作與量測所需的時間和成本,本研究採用數值方法結合元件參數最佳化,通過調整壓電薄板和薄膜的尺寸參數,探討每個參數對振動和聲學特性的影響,將音壓頻率響應曲線最佳化,預期希望設計具有人耳感受良好聲學表現的跑道形揚聲器。故本論文結合理論解析、數值分析和實驗量測,並通過對壓電薄板複合薄膜的聲學元件,嘗試進行最佳化設計,為新型揚聲器的聲音品質和聲場增益特性,提供一可嘗試使用的設計方法。 The research studied the vibration and acoustic characteristics of membranes compounded with piezoelectric thin plates as acoustic actuators. The research involves theoretical analysis, Trefftz’s meshless method, finite element method (FEM), and experimental measurements to verify with the analyzed results. Vibration analysis is conducted for single- and double-connected membranes with rim-fixed boundary conditions, and membrane tension is determined through inverse calculations. Theoretical analysis is also performed for the vibration of piezoelectric thin plates under free boundary conditions. The vibroacoustic characteristics of composite double-layered piezoelectric thin plates with racetrack diaphragm are also studied. Out-of-plane vibration characteristics of the acoustic components are determined by using Electronic Speckle Pattern Interferometry (ESPI) and Laser Doppler Vibrometer (LDV). Acoustic measurements in enclosed sound fields are conducted using an artificial ear. The results in finite element method is validated with the results from experimental measurements obtained from the artificial ear due to the enclosed sound fields. Avoiding time-consuming and cost involved in prototype, this study utilizes commercial finite element software combined with parameter optimization to optimize the sound pressure level, for achieving optimal design for high acoustic performance speakers. By optimizing the acoustic components of membranes compounded with piezoelectric thin plates, an effective approaching for sound quality and acoustic field of racetrack speakers with enhancement is developed in the thesis. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/90060 |
DOI: | 10.6342/NTU202303733 |
全文授權: | 同意授權(全球公開) |
顯示於系所單位: | 機械工程學系 |
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