Please use this identifier to cite or link to this item: http://hdl.handle.net/11455/2586
標題: 懸臂樑結構尺寸與自然頻率及阻尼比關係之研究
The Investigation on the Relationship between Structural Dimensions, Nature Frequency and Damping Ratio of Cantilever Beam
作者: 林奕男
Lin, Yi-Nan
關鍵字: Vibration-power micro generator;振動式微發電機;Nature frequencies;Damping ratio;自然共振頻率;阻尼比
出版社: 機械工程學系
摘要: 
振動式微發電機是基於一平板之振動,使得黏合在平板上之壓電材料受到彎曲所產生之應力而變形,致使壓電材料產生電量;當平板結構位於共振頻率時,相對的其平板結構有最大振幅,而在最大振幅之前後 根號二分之一倍數之位置,相對於頻率會有兩個頻率W1、W2,此頻率之差稱之為頻寬,頻寬為電子工程中計算之有效頻率,由實驗發現阻尼的增加可增加頻寬之寬度,相對的也是增加振動發電時之有效頻率,不過卻也會造成最大電量的下降,要如何利用結構尺寸變化用來調整阻尼的大小,進而得到最佳化之電量產生,是本研究之重點。
本研究首先以電腦模擬方式分析不同結構尺寸懸臂樑之自然共振頻率,再以實驗方式量測各不同元件之自然共振頻率,觀察是否應證模擬數值,進而由實驗數據推算阻尼比值,可探討平板結構懸臂樑長寬高變化與阻尼比變化關係,同時也發現於相同體積下,設計高阻尼比懸臂樑元件,增加長度可得到最佳效果;最後,由於頻寬與阻尼比、自然共振頻率為相依關係,長度、高度結構尺寸改變相對造成阻尼比與自然頻率皆大幅變動,唯有寬度改變情況下,阻尼比變動幅度大且自然共振頻率僅有些微變化,因此可使用寬度參數做頻寬大小設計參數。

Vibration-power micro generator is based on a cantilever plate vibrating. Some piezoelectric material paste on the cantilever plate, then the vibration force makes piezoelectric material deformation and produces electricity. When the cantilever plate is on its structural resonant point, the maximum amplitude will be produced at the same time. It would be two frequencies W1、W2 on the radical half multiple of maximum amplitude, and the deference of the two frequencies is called Bandwidth which is a kind of effect frequency on electronics engineering. According to experiment, we know that adding the magnitude of damping makes bandwidth wider. It means wider effect frequency to produce electricity. Unfortunately, the more effect frequency makes maximum producing electricity down. How to adjust the magnitude of damping with changing the structural dimensions and get the optimum magnitude of electricity is
a key point of this thesis.
In this thesis first, analyzes the nature frequencies of cantilever beams which different structural dimensions with computer simulation. Second, measures the nature frequencies of the different components with experimental method, and compares with the two kinds of nature frequencies if they match. Third, we can use the experimental datum to calculate the magnitudes of damping ratio, then the relation between the changes on length、width、highness of cantilever plates and the magnitudes of damping ratio can be fined. Simultaneously, if we want to design a cantilever plate of high damping ratio in the situation at the same volume, adding length parameter is a best way. Finally, because of the dependent relation between bandwidth and damping ratio、nature resonant frequency, length、highness parameters will cause big variations on damping ratio and nature frequency. However, width parameter causes little variation on nature frequency only. Width parameter can be a design
parameter of bandwidth.
URI: http://hdl.handle.net/11455/2586
Appears in Collections:機械工程學系所

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