斜拉桥拉索振动频率研究理论与实测

发布时间：2018-03-14 19:55

本文选题：索梁耦合　切入点：振动频率　出处：《湖南大学》2014年硕士论文　论文类型：学位论文

【摘要】：斜拉索作为斜拉桥的主要承载构件，由于其具有阻尼低、质量低和全面柔性等基本特点，当桥面振动频率与拉索的固有频率的比值接近一定范围时，桥面小幅振动将引起拉索大幅度的振动，给桥梁结构带来不利影响；拉索的索力值是斜拉桥施工监控和长期健康监测的重要指标，通常通过测试拉索振动频率来获得索力值，因此准确分析斜拉索的振动频率是斜拉桥设计和运营的重要工作之一。本文以此为背景研究大跨度斜拉桥中拉索的振动机理，并对考虑塔/梁运动下的拉索振动频率和索力测试进行了详细的理论分析和实验测试，主要工作如下： 1.在广泛查阅国内外文献的基础上，对于斜拉桥中拉索、梁及索-梁组合结构的动力学及其振动频率研究进行了综述，并着重突出了拉索的振动频率问题。 2.建立了不考虑塔/梁运动下的拉索振动力学模型，基于动平衡法推导出面内面外控制方程，在此基础上利用分离变量法和边界条件得到单索的振动频率和振型，通过数值分析，讨论了垂跨比、倾斜角对拉索振动频率的影响。 3.基于Hamilton原理，利用动静法精细分析了索-梁的连接条件和边界条件，，建立了索-梁组合结构三维面内外运动方程，通过方程约化得到二维控制方程，在此基础上推导出索-梁组合结构的振动频率和振型，然后分析了参数刚度比、垂度比和倾斜角对振动频率的影响。 4.以永鑫大桥为工程背景，利用通用有限元软件ANSYS对其进行动力分析，通过改变模型中的拉索单元划分情况，以研究斜拉索的振动特性并得到一部分拉索的频率值。 5.对永鑫大桥斜拉索进行现场实测和全桥自振频率测试，得到斜拉索振动频率和拉索的索力测试值，并与有限元模型得到的理论频率值和索力值进行对比分析，从而对上述的理论分析进行实验验证。
[Abstract]:As the main bearing member of the cable-stayed bridge, because of its low damping, low mass and overall flexibility, when the ratio of the vibration frequency of the deck to the natural frequency of the cable is close to a certain range, The small vibration of bridge deck will cause large amplitude vibration of cable and bring adverse effect to bridge structure, cable force is an important index of construction monitoring and long-term health monitoring of cable-stayed bridge, and cable force is usually obtained by testing the vibration frequency of cable. Therefore, the accurate analysis of the vibration frequency of stay cables is one of the important tasks in the design and operation of cable-stayed bridges. In this paper, the vibration mechanism of cables in long-span cable-stayed bridges is studied in this paper. The vibration frequency and cable force of the cable under the consideration of tower / beam motion are analyzed and tested in detail. The main work is as follows:. 1. On the basis of extensive reference to domestic and foreign literature, the dynamics and vibration frequency of cable, beam and cable-beam composite structures in cable-stayed bridges are summarized, and the vibration frequency of cables is emphasized. 2. The dynamic model of cable vibration without considering the movement of tower / beam is established. Based on the dynamic balance method, the governing equations are derived, and the vibration frequency and mode shape of single cable are obtained by using the separation variable method and boundary conditions. Through numerical analysis, the effects of vertical span ratio and inclined angle on the vibration frequency of cable are discussed. 3. Based on Hamilton principle, the connection condition and boundary condition of cable-beam are analyzed by using dynamic and static method, and the three-dimensional in-plane motion equation of cable-beam composite structure is established. The two-dimensional governing equation is obtained by reducing the equation. On this basis, the vibration frequency and mode shape of cable-beam composite structure are deduced, and the effects of parameter stiffness ratio, sag ratio and inclination angle on vibration frequency are analyzed. 4. Taking the Yongxin Bridge as the engineering background, the dynamic analysis of the bridge is carried out by using the general finite element software ANSYS. By changing the partition of the cable elements in the model, the vibration characteristics of the cable-stayed cables are studied and some of the frequency values of the cables are obtained. 5. The vibration frequency and cable force of the cable are measured and compared with the theoretical frequency and the cable force of the finite element model. Thus, the above theoretical analysis is verified experimentally.
【学位授予单位】：湖南大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U441.3

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