奈米流體阻尼器性能試驗及溫度效應之研究

Research of Nano-fluid Damper Performance Test and Temperature Effect

林子修(Zi-Xiu Lin)

指導教授 ： 張國鎮

國立臺灣大學/工學院/土木工程學研究所/碩士(2021年)

https://doi.org/10.6342/NTU202103281

摘要

自1900年代被動型液態黏性阻尼器應用至土木工程以來，國內近年也將液態黏性阻尼器作為被動消能元件，廣泛應用於建築物、橋梁或是結構物之興建與補強，然而液態黏性阻尼器仍有許多問題限制其應用，例如:市面上之阻尼器皆透過其內部之物理機構以控制力學行為，不但於研發階段需高成本製作與修改，且工程師於應用階段受到固定之阻尼型號所限；安裝於結構體上之阻尼器身受油封年限所限制，製作阻尼器時須對阻尼器進行加壓導致在靜止階段時即有力量作用於油封上；另外，阻尼器的溫度也直接影響了油封的使用年限，橋梁於車載下即出力過大除了直接對油封造成損耗，累積溫度上升過多也是液態黏性阻尼器面臨的問題之一。
本研究目標為探討奈米流體阻尼器之雙α性能及溫度效應，奈米流體阻尼器是一種液態黏性的速度型阻尼器，具有簡單的物理機構，可經由改變內部填充之奈米流體之配比，控制阻尼器力學公式F=CV^α中之阻尼係數C與非線性係數α。奈米流體阻尼器較一般液態黏性阻尼器的優勢為:較為單純的物理機構可以減少研發及製作成本；阻尼器所填充之奈米流體可依使用需求進行配製調整；不須對阻尼器加壓即可發揮其效果，能有效減低油封消耗；具備雙α值之特性使阻尼器於小擾動下所產生之阻尼力較傳統阻尼器來的小，累積能量小進而使升溫情形也較傳統阻尼器緩。
本研究所採用之阻尼器填充流體以聚丙二醇(Poly Propylene Glycol, PPG)為載液，二氧化矽奈米顆粒作為溶質，以PPG分子量及二氧化矽奈米粒子的重量百分濃度為操縱變因，配製出一系列的奈米流體。並設計製作實體具有雙桿及環間隙之阻尼器，透過更換不同流體來進行阻尼器實體試驗驗證奈米流體阻尼器的雙α性能，進行一系列溫度試驗比較奈米流體阻尼器受溫度效應下的性能差異，及探討環境溫度與累積能量造成升溫的影響。另外，由熱力學建立溫度預測模型與上述實驗結果進行驗證其準確度。最後，工程應用分析方面，將溫度預測模型應用在實際橋梁實驗進行預測，比較奈米流體阻尼器與傳統阻尼器於橋梁應用時溫度上升情形，驗證奈米流體阻尼器能於車載振動下減少溫度上升的特性；隔震結構物分析，選取台灣大學土木研究大樓作為分析模型，透過ETABS進行結構分析，針對阻尼器於不同地震波下之位移與出力歷時進行比較，驗證奈米流體阻尼器能有效發揮隔震墊的優勢。

關鍵字

液態黏性阻尼器 ； 奈米流體 ； 溫度效應 ； 熱力學

並列摘要

Since passive fluid viscous dampers were applied to civil engineering in the 1900s, viscous dampers are widely utilized in buildings, bridges and structures as passive damping energy dissipating element. However, the dampers on the market adjust their mechanical behaviors through altering physical geometry, having high-cost production and modification in both the developmental and manufacturing phases. In addition, when dampers undergo long-term displacement histories, the temperature rises within the fluid of the damper may damage its end-seals and trigger the failure of the damper.
The study is dedicated to investigating the dual alpha performance and temperature effect of nano-fluid viscous dampers, with simple physical mechanisms and the suitable compound ratio of the nano-fluids, nano-fluid dampers can adjust the damping coefficient C and non-linear coefficient α in the mechanical formula : F=CV^α.
In this study, the fluid solvent and solute filling in nano-fluid viscous dampers are poly propylene glycol (PPG) and silica nanoparticles. The independent variables of the nano-fluid are PPG molecular weight and fluid concentration. The damper with a double rod and annular gap was designed. Moreover, different nano-fluids were filled to verify their performance. The performance test also considered the influence of the damper’s temperature. In addition, the temperature prediction model was established by thermodynamics and the above-mentioned experimental results verify its accuracy. Finally, in engineering application analysis, the temperature rise of nano-fluid dampers and traditional dampers are compared through the test and the temperature prediction. And for seismic isolation structure analysis, the displacement and force of different dampers were compared to verify the advantage of the nano-fluid damper.

並列關鍵字

viscous damper ； nano-fluid ； temperature effect ； thermodynamics

參考文獻

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