- 學位論文
貼覆及夾芯黏滯阻尼樑之振動分析
Vibration analysis of a beam with free and constrained damping layers
摘要
本文是以樑含有黏滯阻尼作動態特性研究，為了方便作分析，本文利用傳遞矩陣法作分析，再以消散能等效原理，將阻尼均勻融入在主樑其不改變阻尼效益。阻尼層配置方式有兩種，第一種阻尼配置位於樑表面為貼覆黏滯阻尼層，另一種位於樑的中性軸為夾芯黏滯阻尼層。分別針對阻尼層的位置、阻尼層長度、阻尼值的大小在自由振動與強迫振動探討其抑制振動效果。由結果顯示每項參數對自然頻率皆有影響。強迫振動方面阻尼層貼覆位置不同其初始位移響應衰減率會有很大的差異性。當受到均佈載重影響，貼覆阻尼層的動態特性與彎矩變化有關；夾芯黏滯阻尼動態特性與剪力有關。最後；再以數值模擬與ANSYS軟體作定性驗證分析，分析結果貼覆阻尼與夾芯阻尼對抑制振動效果較佳。
並列摘要
In this paper, the dynamic characteristics of a beam with viscous damping layers are studied. For convenience to analyze by transfer matrix method, the concept of equivalent dissipated energy is utilized to transform the damping layers to be uniformly soloed into the beam body without changing thesis damping effect. There are two kinds of damping layers disposition. One is damping layer on beam that is free damping layer. The other is on neural axis of beam that is constrained damping layer. In accordance with damping layer position, damping layer value, damping layer length for free vibration and forced vibration to discuss which restrain vibrate effetely. The results show that each parameters of the natural frequencies are influenced. The forced vibration on damping layer is on different positions that can great influence initial displacement response. When the distrusted load on the beam, the dynamic characteristics of free damping layer with changes in the moment diagram; the dynamic characteristics of constrained damping layer with changes in the shear diagram. Finally; the numerical simulate and ANSYS do qualitative analysis certification. The result of analysis, free damping layer is great effetely than constrained damping layer on restrain vibration.