索梁耦合振动对拉索阻尼器的影响机理

Effects and Cause of Coupling Vibration Between Girder and Cable on Performance of Cable Dampers for Cable-Stayed Bridges

为了解斜拉桥索梁耦合振动对拉索阻尼器减振效果的影响,建立了由拉索、主梁和线性粘滞阻尼器组成的理论模型,采用无量纲和复模态分析方法详细研究了索梁耦合振动对拉索附加阻尼器减振效果的影响,并与通用设计曲线法得到的结果进行了对比。结果表明,索梁的同相位耦合振动会大幅降低拉索阻尼器的减振效果且耦合程度越高,拉索阻尼器的效果就越差。通过分析阻尼器活塞的绝对位移发现,阻尼器减振效果的降低主要是由于主梁与拉索同步振动、阻尼器活塞相对速度降低、出力减小造成的。

In order to understand the effects of coupling vibration between girder and cable on performance of cable dampers,the model comprised by cable,girder and damper is founded to study the effects.Dimensionless and complex modal analysis methods are applied to analyze the relationship between the coupling vibration mentioned above and the performance of cable damper.Results with and without the coupling vibration are compared for discussion.The results indicate that the performance of cable damper will decrease greatly when the coupling vibration happens.The higher the degree of coupling is,the worse the effect of cable damper is.The small absolute displacement of damper′s piston caused by the very small vibration phase shift of girder and cable is the main cause of the negative impact mentioned above.