本文主要目的為探討被動式吸振器應用於結構多模態減振，應用於受外力而振動之懸臂樑，藉由將樑之表面貼上陶瓷壓電片，再設計雙迴圈電路搭配電阻、電感、電容、二極體而組成的被動式吸振電路，以達到懸臂樑之減振效果。 文中首先使用漢米爾頓原理推導懸臂樑與壓電材料耦合之結構方程式，接著推導吸振電路方程式，並將結構方程式與電路方程式進行耦合，最後使用數值程式求解系統之位移響應。並設計不同的電路與變化參數，得出減振效果較佳的吸振器電路設計，最後透過實驗驗證數值分析之結果。依數值與實驗結果觀察，此種具上下迴路之被動吸振器可達到多模態的吸振效果。 ;The purpose of this research is to develop a newly designed passive piezoelectric absorber for reducing multi-mode vibration of a cantilever beam excited by an external force. A tranditional passive piezoelectric absorber consists of a piezoelectric shunt attached to the structure, a resistance, and an inductance. The new absorber introduced here includes an additional passive loop in parallel. In the thesis, the equations of motion of the beam are derived by using Hamilton’s principle and discretized by Galerkin’s method. Numerical program is developed to simultaneously solve the equations of motion of the beam, which is coupled with circuit equations of the absorber. Different designs of the absorber circuits and different values of parameter are used to find the better results. The numerical results are confirmed by experimental results. According to the present results, the new passive absorber can achieve more vibration reduction of a structure than the tranditional passive absorber.