Development and Application of Vibration Isolation System with Adaptive Stiffness Considering Strong Ground Motions
|關鍵字:||勁度可變;隔震系統;LSCIS;MEW;結構控制;半主動控制;速度能量;Potential energy;Semi-active control;near-fault;energy of velocity|
|摘要:||近年來，結構物隔減震研究日趨受到重視，過去的隔減震研究顯示，隔減震效應因無法即時判定地震類型，並針對近遠域地震不同而改變與達到最佳控制效果。為了使控制效果最佳化，本研究開發一套半主動控制系統「能量比例法」(Feed-forward Predictive Earthquake Energy Analysis ,FPEEA)，透過量測地震速度，並藉由傅立葉轉換(FFT)計算頻率域之能量，由能量可區分出近遠域地震，同時結合最佳動位能比例法(Minimal Energy Weighting, MEW)以達到即時控制降低結構反應。本研究已開發完成此半主動控制理論，並利用槓桿式可變勁度隔震系統(Leverage-type Stiffness Controllable Isolation System, LSCIS)，調整槓桿支點位置進而改變隔震層勁度，以達到最佳的隔減震效果。與過去的半主動控制律相比，本研究之控制律可達到與MEW相同之控制效果甚至更佳。藉由實際振動台試驗，結果顯示速度能量判定可於主要震波來前區分出近遠域地震，達到即時控制效果。在近域地震情況下，FPEEA/MEW控制律可有效降低隔震層位移，並對上部結構加速度反應有良好的控制成效。|
In recent years, the research of isolation and mitigation system has been getting more and more important. In the past isolation and mitigation system, the effect would be reduced because of unknown earthquake types. To have the best effect of response reduction, the systems have to be automatically changed with the earthquake type. To achieve that, an upgraded algorithm, Feed-forward Predictive Earthquake Energy Analysis (FPEEA), is proposed by considering the energy of earthquake velocity and combined with MEW method to have the optimal response. The new algorithm is starting with defining the energy of velocity to have the optimal weighting of MEW. With the optimal weighting defined, MEW method, combination of the potential energy and the kinetic energy, can reduce the structural responses efficiently and on time. In order to demonstrate the performance of the proposed algorithm, a single-degree-of-freedom structure is used as a benchmark in both numerical simulation and experimental verification. With defining the optimal weighting in advanced, the type of earthquake can be defined before the main wave of earthquake comes. The results have shown that the dynamic response of the structure can be effectively alleviated on time. Also, comparing to the structural responses of the MEW method, the proposed algorithm is similar to MEW or even better. The energy of velocity can be known to define the optimal weighting before the main wave comes. With this advantage, the shaking table test shows that the structural responses of experiment are similar to theory and under control in real- time.
|Appears in Collections:||Thesis|