調諧水柱消能系統之分析與試驗

Abstract

調諧水柱消能系統(TLCD)為單自由度之非線性動力系統，具備調頻容易、效能佳、兼具消防及抗振功能、維修需求低、經濟效益高等優於調諧質塊消能系統(TMD)之優勢，未來有成為高樓減振系統主流之勢。TLCD本研究的目的在發展TLCD系統之核心技術以利未來之實際應用包括建立TLCD系統之非線性理論分析模式，分別考慮等斷面與三段式變斷面U型管之情況，並製作一組等斷面TLCD系統進行元件測試與性能測試(振動台試驗) 。此外，並完成參數分析以掌握TLCD系統之最佳設計。元件測試結果顯示， TLCD系統之理論振動頻率與元件試驗所得之頻率十分吻合。儘管TLCD研究之相關文獻多將水頭損失係數考慮成常數，本研究發現水頭損失係數其實與閥門孔徑大小及擾動振幅等有關， 閥門孔徑愈小時，水頭損失係數愈大；水柱激盪振幅愈大時，水頭損失係數愈小。性能測試結果顯示，結構安裝TLCD系統後，無論結構自由振動試驗或地表簡諧波擾動試驗均顯示TLCD系統有良好的減振效果。參數分析結果顯示， TLCD系統之水平段長度與有效長度之比在0.55~0.75間效率較佳，在此範圍內比值愈大時，控制效果愈好；當水平段長度受限時，增加U型管垂直段之管徑可提升控制效果。此外，根據本文所提出之系統識別方法識別水頭損失係數進行非線性數值分析，水柱激盪位移及結構振動反應預測值均與試驗結果相當契合，驗證本文所提非線性理論分析模式之精確性，可供未來實際應用時設計分析之用。

Tuned Liquid Column Damper (TLCD) is a nonlinear single-degree-of-freedom system that possesses advantageous features such as easy-tuning, efficient, dual functions (fire protection and vibration damper ), less maintenance and cost-effective as compared with TMD systems .It is expected to become the main-stream system for vibration control of high-rise buildings. The objective of this study is to develop the know-how of TLCD systems for real-world application. The tasks include establishing analytical models for the nonlinear TLCD systems of uniform as well as 3-segment variable tube diameters, and conducting a series of component test and performance test (shaking table test) of a prototype uniform TLCD system. Moreover, parametric studies have been explored to get more insight of the optimum design of TLCD systems. Experimental results from the component test indicate agreement of the fundamental frequency with the theoretical prediction. While the headloss coefficient has been considered a constant in the literature, it is found to actually depend on the opening size of the valve and disturbing amplitude. The smaller the opening size, the larger the headloss coefficient.; and, the stronger the disturbing amplitude, the smaller the headloss coefficient. Experimental results from the performance test indicate that TLCD is effective in structural vibration control in both free vibration and harmonic excitation. Parametric analysis further indicates that the efficient length of the horizontal portion of the U-tube ranges from 0.55~0.75 of the effective length, within which the longer the horizontal part the better the controlling effect. However, if the horizontal portion is constrained due to practical considerations, increasing the diameter of the vertical tube (variable diameter case) also promotes the controlling effect. Moreover, the numerical predictions of the liquid sloshing displacement and structural responses with the headloss coefficient identified by the proposed system identification scheme agree very well with the test data, verifying adequacy of the proposed analytical model that provides the basis for design and analysis of practical application in the future.