大跨度斜拉索参数振动研究

Research on Parametric Oscillation of Super Long Cables

针对大跨度斜拉桥拉索的参数振动问题,利用三主梁建立模型的有限元方法计算三塔斜拉桥动力特性,并计算单根拉索动力特性。通过频率比较得出易于发生参数振动的拉索。取两个典型长索进行分析,通过有限元和数值积分两种方法比较讨论各种因素(激励频率、激励振幅、阻尼)对索参数振动的影响。结果表明:当索频率和全桥频率成一定比率时,极易发生大幅度参数振动,对桥梁的使用和安全有不利影响。

In order to consider the parametric oscillation of the cables of super long cable-stayed bridges,triple-girder finite element model is built to obtain the global modes.Also,the modes of the cables are calculated and by comparing the cables in which parametric oscillation may occur are found out.Take the examples of two typical cables,two methods including finite element method and numerical integration are used to analyze the influences of various factors（frequency and amplitude of the excitation,damper）.Results show that parametric oscillation will be very likely to happen when the frequencies of the cables is proportional to the global frequencies,which can do harm to the security and durability of the bridges.