本研究嘗試將線性黏性阻尼器應用於纜索減振策略,執行裝設阻尼器之斜張橋纜索減振效用評估。首先,介紹裝設線性黏性阻尼器之繃緊纜索自由振動的複數振態分析理論模式,包含複數特徵值問題、無衰減振動、趨近於臨界阻尼之振動,以及阻尼器引致頻率偏移等四部分內容;接著,接續理論模式,提出數值算例,係以有限元素法為工具,分別建立水平繃緊纜索、不對稱單塔斜張橋、對稱雙塔斜張橋,以及高屏溪斜張橋等四類模型,並進行系統振態自然頻率分析、系統振態耦合度分析、系統振態阻尼比分析,以及系統動力分析。經由本研究成果可全面地瞭解裝設線性黏性阻尼器之斜張橋纜索的力學機制,並合理地預測線性黏性阻尼器之減振效用。
The objective of this study is to fully understand the dynamic characteristics of stay cables with attached linear viscous dampers as well as to reasonably assess the vibration reduction effectiveness of the dampers. The free vibration theory of taut cables including the complex eigenvalue problem, nondecaying oscillation, oscillation approaching critical damping and damper-induced frequency shift are introduced for this purpose. To validate the theoretical models, numerical examples including a horizontal taut cable, unsymmetrical single-tower cable-stayed bridge, symmetrical twin-tower cable-stayed bridge and Kao Ping Hsi cable-stayed bridge are provided to conduct the modal natural frequency analysis, modal coupling analysis, modal damping ratio analysis and dynamic analysis based on the finite element method. The results of this research are demonstrated to fully understand the mechanism of stay cables with attached linear viscous dampers as well as to accurately predict the effectiveness of the dampers.