一般撓性結構在高速運轉時，容易受簡諧外力作用而產生橫向振動，如轉子偏心不平衡或裝置不對心所造成的離心力，產生過大的振幅，導致結構的破壞或受損，本文的主要目的即是探討壓電吸振器應用於旋轉樑的減振效應。 本文模擬一兩端簡支撐的雷立夫樑，在樑上受到一簡諧集中力激振，並假設外力頻率和轉動速度相等。文中分析此旋轉系統的動態特性，並嘗試將壓電材料貼附於旋轉樑表面，再配合電感、電阻與適當的電路，形成類似機械式吸振器的裝置。由於壓電材料具有機械能和電能互換的特性，當系統受力而產生變形與振動時，壓電材料會因應變而產生電場，其外加的電路會消耗因壓電材料變形產生了的電能，以減少系統的振動量。 本文是由能量法的觀點出發，根據漢米爾頓定理來推導旋轉樑貼上壓電材料的運動方程式，並配合壓電吸振器的電路方程式而形成一偏微分方程組，再利用格勒金法將系統離散化，求出系統的位移解，最後以數值模擬分析。本文採用被動式吸振器控制系統，文中分別針對壓電吸振器可調變的參數作探討，進而得知壓電吸振器對於系統減振的特性。 The forced vibration of a flexible beam rotating about its longitudinal axis is easy to produce excessive vibration and failure. In general, the external force is the centrifugal force caused by the unbalanced rotor or misalignment. The purpose of this study is to reduce the vibration of a rotating beam by using piezoelectric absorbers. Piezoelectric materials shunted with a resistor and an inductor is similar to a mechanical vibration absorber. The general model is a rotating Rayleigh beam, simply supported ends, surface-bonded with two pairs of piezoelectric absorbers. The equations of motion of the composite rotating beam are derived by Hamilton’s principle and discretized by Galerkin’s method. The dynamic response of the model subjected to the harmonic force is solved. Various designs of the absorbers are discussed in this thesis. The numerical results show that the absorbers are effective for reducing the vibration of the rotating beam.
