斜拉桥拉索的参数振动有限元分析

ANALYSIS OF THE PARAMETER VIBRATIONS OF THE CABLE IN CABLE-STAYED BRIDGE BY FEM

为探讨斜拉桥拉索发生大幅参数振动的条件，以及在振动过程中拉索的振幅和张力波动的特点，本文利用作者建立的几何非线性结构非一致激励响应分析方法，进行了斜拉索的参数振动有限元分析。分析表明：桥面的面内激励易使斜拉索的振动包含面外对称振型，从而出现组合振动现象；而桥面的面外激励只激起面外对称振动，不易引起斜拉索的面内振动；增加斜拉索的阻尼可抑制其振幅，缩小其发生大幅振动的频率范围，但其张力波幅却相应增加。所得结果与以往研究者的解析结果及实验观测现象相一致。

This paper is concerned with the characteristics of the parameter vibrations of the cable in cable-stayed-bridge, especially the vibration amplitude and the tension fluctuation. Using the method for geometric non-linear response analysis of structures under asynchronous excitation developed by the authors, the behavior of the parameter vibration of one cable-stay is studied using FEM. It is observed that the in-plane vibration of the deck can induce the out-of-plane symmetric vibration modes of the cable easily, leading to coupling vibration. However, the out-of-plane vibration of the deck can only induce the out-of-plane symmetric modes, and cannot induce the in-plane vibration of the cable easily. It is also found that the increase of damping of the cable dwindles the frequency bandwidth of large-amplitude vibrations and reduces the amplitude of vibrations, but enlarges the tension fluctuation. The results are in agreement with available analytical results and experimental phenomena.