雙指數奈米流體阻尼器之研發與應用

Development and Applications of Nanofluid Viscous Damper with Dual Nonlinearity

彭聖凱(Shen-Kai Peng)

指導教授 ： 張國鎮

國立臺灣大學/工學院/土木工程學研究所/博士(2022年)

https://doi.org/10.6342/NTU202203322

摘要

黏性阻尼器已廣泛應用於結構耐震設計，而現今其性能主要取決於活塞頭的複雜機械設計。本研究所發展的雙指數奈米流體阻尼器，其內部構造僅包含實心之活塞頭和其外圍之環形間隙，並且可以通過簡單地調整所填充奈米流體的成分比例，來實現所需的阻尼特性，可滿足結構需求，提升控制精度。並因奈米流體之特性，使雙指數奈米流體阻尼器於力量與速度之關係上，具有雙指數之力學特性。應用於橋梁，可以降低平時溫差或行車作用下阻尼器之內壓與油封之磨耗，大幅提升阻尼器之耐久性；應用於隔震結構，可以使隔震系統於中小地震下充分發揮隔震效果，並且不影響設計地震下的消能行為。
本研究首先依據奈米流體流變特性試驗與理論模型，設計製造兩組阻尼器，並從試驗結果驗證數值模型之可靠性及其雙指數特性，使將來可由有限的阻尼器試驗透過理論公式設計出符合需求的奈米流體阻尼器。接著結合阻尼器升溫試驗建立包含熱傳模組的奈米流體阻尼器CFD模型，輔助了解其升溫機制並能以之推估阻尼器的溫度與出力。之後採用實際橋梁車載試驗之數據，驗證於橋梁車行振動下，所消散之能量大幅低於傳統黏性阻尼器，其意味著小振動所造成之耗損較低，因此具有較佳的耐久性，並以歷時分析印證其在設計地震下依然保持良好的消能能力。最後也建立狀態空間模型進行隔震結構之非線性歷時分析，驗證不論在設計地震或中小度地震時，安裝理想化奈米流體阻尼器之隔震系統皆較能抗震，成功演示了雙指數奈米阻尼器於隔震應用之可行及有效性。

關鍵字

雙指數阻尼器 ； 奈米流體 ； 剪切增稠流體 ； 計算流體力學 ； 狀態空間

並列摘要

In seismic design, the viscous damper has been widely used, and its performance is now primarily determined by the complex mechanical design of the piston head. However, a nanofluid damper, which features dual nonlinearity exponents in force-velocity curvature, can be precisely manufactured with simple mechanisms and adjustable fluid properties for efficient structural control requirements. Applied to bridges, it can prevent damper seals from wearing out under daily vibrations and will greatly improve the damper's durability. Furthermore, the application of nanofluid dampers to the isolation structure allows the isolation system fully exert under service level earthquake.
In this study, two sets of dampers are designed and manufactured based on the nanofluid rheological characteristics and theoretical model. The experimental findings confirmed the model's validity and dual exponential characteristics. Then, in conjunction with the damper heating test, a CFD model of the nanofluid damper, including the heat transfer module, was created to understand its heating mechanism and help estimating the damper's temperature. Moreover, the advantage of low energy dissipation, which could considerably increase durability under mild vibration, was verified through an actual bridge vehicle test. Finally, a state-space model was established to conduct the nonlinear time analysis of the isolation structure. It was verified that the isolation system installed with idealized nanofluid dampers was more resistant to earthquakes regardless of design basis or service level earthquake.

並列關鍵字

dual nonlinearity exponents damper ； nanofluid ； shear thickening fluid ； CFD ； state-space

參考文獻

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