摘要: | 本文主要目的在探討壓電式碰撞吸振器應用於懸臂樑的減振效果。在懸臂樑的表面適當位置處,貼附成對壓電材料,並外接由電阻及電感等電子元件組成的吸振電路,形成具有減振效果之吸振器,而本文之吸振電路形式為標準式被動吸振電路並聯一個二極體與其他電子元件,如電感與電阻,並藉由二極體的導通與不導通的切換情形,模擬機械系統中的碰撞運動,此即文中所謂之壓電式碰撞吸振器。 首先假設施予樑上的外力形式為簡諧集中力,且令外力激振頻率等於懸臂樑與壓電材料之複合系統的第一自然頻率,接著使用漢米爾頓原理推導懸臂樑與壓電材料之耦合運動方程式,並將其與吸振電路方程式作聯立,最後利用數值方法求解聯立方程式,解得系統之位移響應。透過各種分析結果,說明此一壓電式碰撞吸振器確實有優於標準式被動吸振器之減振效果,同時也說明此一壓電式碰撞吸振器可藉由二極體的導通與否,模擬機械系統中的碰撞運動且造成能量的損耗。 The purpose of this research is to reduce the vibration of a cantilever beam by using piezoelectric impact absorbers. Each absorber consists of a piezoelectric sheet, inductances, resistances and a diode which simulating the mechanical impact effect by switching of the circuit on and off. A composite cantilever beam is subjected to an external harmonic force with its frequency equal to the natural frequency of the beam. The equations of motion of the beam are derived by Hamilton's principle and discretized by Galerkin's method. The equations of motion of the beam and the circuit equations of impact absorbers are solved simultaneously. The numerical results show that piezoelectric impact absorbers are more effective than the traditional piezoelectric absorbers. |