- 學位論文
螺旋彈簧包覆阻尼層之振動分析
Vibration analysis of a helical spring coated with damping layer
摘要
本文中將螺旋彈簧包覆阻尼層，以電腦輔助工程(CAE)軟體分析螺旋彈簧的動態特性。建構沿螺圈表面包覆螺旋狀阻尼層及完全包覆螺圈之圓柱狀阻尼層模型後，再以有限元素分析軟體進行自然頻率(Nature frequency)及暫態響應分析(Transient response analysis)，由不同包覆厚度比(Tr)、圈數比(Nc)及包覆位置探討阻尼層對結構振動之影響，並以初始位移後之自由振動振幅衰減指數值為減振指標。 由分析結果可知，自然頻率的變化主要受質量效應影響。包覆螺旋狀阻尼層時，自然頻率隨Tr、Nc增加而下降；包覆圓柱狀阻尼層時，相同Tr之自然頻率因軸向剛性大於質量效應而隨Nc增加而上升，反之，相同Nc之自然頻率則因質量效應大於軸向剛性而隨Tr增加而下降。 包覆相同質量阻尼層時，圓柱狀阻尼層之減振效果較好；兩種阻尼層在由自由端及固定端包覆時，分別增加Tr及Nc可有效提升減振效果。
並列摘要
In this study, the damping material is coated of helical spring. The CAE software is utilized to analyze the dynamic characteristics of the structure. Two damping models are constructed, respectively are coating along the helical wire surface and coating around the wire into the hollow cylindrical. Use the FEM software to analyze the nature frequency and transient response. The vibration reduction effect due to coated damping layer with various coating thickness ratio (Tr), coils ratio (Nc) and positions are evaluated. The vibration reduction is indicated by the decay rate of the amplitude of the free vibration due to initial deformation. The result shows the nature frequency varies with damping mass. The nature frequency decrease with increasing Tr and Nc when coating the helix damping layer. As coating the cylindrical damping layer, the nature frequency increase with increasing Nc at the same Tr because of the axial stiffness is greater than the mass effect, on the other side, the nature frequency decrease with increasing Tr at the same Nc due to the mass effect is greater than the axial stiffness. At the same mass, the vibration reduction with cylindrical coating is greater than the helix coating. When the damping layer position are from the free and fix end, respectively increased Tr and Nc can effectively enhance the vibration reduction.