多塔斜拉桥拉索面内外振动理论及有限元分析

发布时间：2018-05-22 08:14

本文选题：多塔斜拉桥 + 拉索　；参考：《长安大学》2015年硕士论文

【摘要】：斜拉桥因其美观的造型和较强的跨越能力,成为倍受现代设计师们青睐的一种桥型。作为斜拉桥关键部件的斜拉索,具有质量小,阻尼低和柔度大的特点,在风荷载、车辆荷载等作用下斜拉索容易发生大幅度的振动。拉索的振动容易加速拉索的疲劳,最终导致拉索的破坏,直接影响桥梁的使用安全。因此,对斜拉索振动特性的研究已经成为斜拉桥设计的一个重要环节。由于多塔斜拉桥刚度不足,自身容易发生振动现象,同时也易导致拉索的共振,所以如何提高多塔斜拉桥刚度已经成为当今桥梁建设领域的热议话题之一。为了研究多塔斜拉桥刚度对拉索振动的影响程度,本文首先建立了不同主梁刚度、桥塔刚度的有限元模型,讨论刚度对于成桥动力特性的影响。接着在建立了三维空间内的拉索面内-外-桥面耦合振动模型,得到了拉索面内-外-桥面耦合振动方程组,采用多尺度法分析了拉索面内-外-桥面耦合振动特性。最后,通过计算边塔拉索的面内外固有频率,与不同工况成桥的频率进行对比,分析可能发生大幅共振的拉索以及其面内外的振动特性。结果表明,多塔斜拉桥主梁刚度对于拉索发生面内外共振的可能都有一定的影响,对面内共振振幅影响大,而桥塔的刚度则对共振幅值影响很小,成桥的整体刚度则对拉索振动发生的可能影响强烈。
[Abstract]:Because of its beautiful shape and strong span ability, cable-stayed bridge has become a bridge type favored by modern designers. As a key component of a cable-stayed bridge, the cable has the characteristics of low mass, low damping and large flexibility. Under the action of wind load and vehicle load, the cable-stayed cable is easy to vibrate in a large amplitude. The vibration of cable accelerates the fatigue of the cable and leads to the damage of the cable, which directly affects the safety of the bridge. Therefore, the study of cable vibration characteristics has become an important link in the design of cable-stayed bridge. Due to the lack of stiffness of multi-tower cable-stayed bridge, it is easy to vibrate itself and lead to the resonance of cable, so how to improve the stiffness of multi-tower cable-stayed bridge has become one of the hot topics in the field of bridge construction. In order to study the influence of multi-tower cable-stayed bridge stiffness on cable vibration, the finite element model of different main beam stiffness and bridge tower stiffness is established in this paper, and the influence of stiffness on the dynamic characteristics of the bridge is discussed. Then, the coupling vibration model of cable plane and external bridge deck in three dimensional space is established, and the coupling vibration equations between cable plane and external bridge deck are obtained. The coupling vibration characteristics of cable plane and external bridge deck are analyzed by using multi-scale method. Finally, by calculating the natural frequencies in and out of plane and comparing with the frequencies of the bridge under different working conditions, the vibration characteristics of the cables which may have large resonance and the vibration inside and outside the plane are analyzed. The results show that the stiffness of the main girder of the multi-tower cable-stayed bridge may have a certain effect on the in-plane resonance of the cable, and the amplitude of the resonance on the opposite side has a great effect, while the stiffness of the tower has little effect on the co-amplitude. The overall stiffness of the bridge may have a strong effect on the vibration of the cable.
【学位授予单位】：长安大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U448.27

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