具斜交黏滯阻尼器之幾何非線性隔震系統的開發與性能分析

Development and Performance Analysis of Seismic Isolation Bearings With Angled Viscous Damper

10.6849/SE.202409_39(3).0003

劉倢妤(Chieh-Yu Liu)；張家銘(Chia-Ming Chang)

隔震系統 ； 幾何非線性 ； 多目標性能 ； seismic isolation ； geometric nonlinearity ； multiple performance objectives

結構工程

39卷3期（2024 / 09 / 01）

43 - 62

繁體中文;英文

地震發生可能導致醫療設備及廠房精密儀器毀損，甚至造成嚴重經濟損失及生命危害。為此，過去普遍應用基底隔震達到降低受震反應，該策略是透過安裝隔震系統，進而延長結構或設備的振動週期，有效降低地震對上部結構之傳導。然而，研究指出當地震規模較大時，基底隔震系統可能產生過大位移，需適當增加隔震系統之阻尼以降低位移量。隔震系統阻尼之需求，通常是基於設計地震力進行設計，導致在中小地震時，阻尼過大，隔震效果不佳，缺乏適應不同地震規模的能力。為此，本研究開發一種具斜交阻尼器的幾何非線性隔震系統，應用幾何之概念，調節阻尼器出力，確保在不同規模之地震作用下達到對上部結構或設備物之保護。首先，本研究透過對幾何非線性阻尼進行動力特性分析以瞭解整體非線性行為，接著利用平均法獲得頻率域下外力－位移以及絕對加速度之關係。為了評估系統在真實地震下的性能表現，引入高雄美濃地震進行實際模擬，並定義三個性能指標來評估時間域的動態行為。最後，應用滾動型單擺支承及黏滯阻尼器結合，並透過幾何配置進行振動台實驗以驗證數值模型可靠性，進而證明幾何非線性系統具對外力之適應性與多目標性能。

Earthquakes pose a significant impact on machinery requiring high-precision manufacturing in advanced facilities. Meanwhile, severe earthquakes cause enormous economic losses and threaten lives. Base isolation is a popular method for controlling seismic impact, extensively employed to mitigate structural response and lessen seismic risk. However, certain studies suggest that base isolation could lead to excessive displacement during severe earthquakes. To enhance safety and functionality, supplemental damping is recommended to be integrated into the isolation system to mitigate large displacements. However, isolation parameters are typically designed for design-level earthquakes, resulting in increased absolute acceleration during small-to-moderate earthquakes and limited displacement control capacity during large earthquakes due to the lack of adaptability in damping. This study proposes an isolation system with geometrically nonlinear damping and first examines the dynamic characteristics. Subsequently, the relationship between seismic input and isolation responses in the frequency domain is analyzed using the averaging method. The seismic performance of the proposed system is then evaluated using earthquake records from the 2016 Kaohsiung Meinong earthquake to assess time-domain performance set at various initial inclining angles. Through a series of investigations, it is observed that the geometrically nonlinear damping configuration offers advantages by providing adaptive damping forces to isolation bearings and achieving multiple performance objectives across different earthquake magnitudes. Additionally, the proposed isolation system with a geometrically nonlinear viscous damper is experimentally validated to confirm the displacement-force relationship through shake table testing. In the experimental setup, the isolation system comprises three single-curvature grooves moving on fixed ball bearings alongside an angled linearly viscous damper. During the test, this isolation system is subjected to harmonic excitation on a uniaxial shake table to obtain force-displacement behaviors. The results demonstrate a close behavior between the simulated force-displacement relationship and the experiment, thus indirectly carry out the multiple performance objectives of the proposed system against earthquakes.