外激励作用下斜拉桥索-梁相关振动特性

为了研究大跨度斜拉桥在外激励作用下发生的索-梁相关振动,基于非线性振动理论建立了拉索发生大幅度非线性振动的理论方程,开发了有限元索动力单元;建立了某大跨度斜拉桥全桥有限元模型,在此基础上,使用索动力单元模拟斜拉索;最后,以一座具有代表性的大跨度公路斜拉桥为例,研究了在不同工况的外激励作用下斜拉桥发生索-梁相关振动的特性.研究结果表明:在斜拉桥全桥尺度下研究索-梁相关振动更为合理;斜拉桥的索-梁相关振动是一个能量传递过程;在外激励作用下,拉索 1:1 主共振更容易发生,2:1 参数共振相对不容易发生;靠近桥塔位置的较短拉索不容易发生较大幅度的振动. 

Cable-Beam Vibration Characteristics of Cable-Stayed Bridge under External Excitations

To understand the effect of external excitations on the cable-beam vibration of large-span cable-stayed bridge, firstly, the theoretical equation for the large-amplitude cable vibration was built, and based on nonlinear vibration theory, the dynamic cable element was developed using finite element method(FEM). Secondly, a large cable-stayed bridge FEM modal was built, and the cables of the bridge were simulated by cable dynamic element. Finally, a typical cable-stayed bridge was used as an example to investigate the cable-beam vibration characteristics under different external excitations. The results indicate that it is more reasonable to study the cable-beam vibration on global bridge scale. In cable-beam vibration, there is an energy transfer process. Under external excitations, 1:1 main resonance more easily occurs than 2:1 parametric resonance. The shorter cables close to the towers in cable-stayed bridge are difficult to experience large-amplitude vibration. parametric resonance, main resonance of cable occur more easily. The shorter cables which near by the towers in cable-stayed bridge are difficult to occur large amplitude vibration.