大跨度悬索桥的刚度退化机制与静风稳定性研究
发布时间：2018-11-03 13:11
【摘要】：过去，大跨度悬索桥的抗风研究主要集中在结构的动力失稳及抖振响应问题上。而对其在风荷载作用下，由于主缆刚度退化而引起的静力扭转发散现象却未给予同等的重视。近年来风洞试验和研究表明，，随着桥梁的长细化，大跨度桥梁很可能发生静风失稳现象。因此，有必要对大跨度悬索桥的静风失稳机理进行全面的研究。 本文在已有研究文献的基础上基于谐波合成法的原理，采用三次均匀样条插值方法实现了大跨度桥梁随机脉动风速的快速模拟。采用动力有限元方法求解了紊流场中大跨度悬索桥的静风稳定问题。进一步完善了大跨度悬索桥结构的刚度退化及扭转发散机制。研究了主缆竖向变形和侧向变形对主缆系统扭转刚度的影响。最后，对大跨度悬索桥的风致响应进行了参数分析。论文的主要工作如下： （1）介绍了大跨度桥梁静风稳定问题的基本概念，综述了大跨度桥梁静风稳定问题的分析理论及其求解思路。 （2）采用谐波合成法并通过三次均匀样条插值方法实现了大跨度桥梁随机脉动风速的快速模拟。 （3）分别采用荷载增量与内外双重迭代相结合的方法(静力有限元法)和动力有限元法求解了均匀流场中大跨度悬索桥的静风失稳临界风速，结果表明：两种方法得出的结果是一致的。 （4）基于梁-索广义模型，推导了主缆系统的广义扭转刚度表达式，并建立系统的广义运动方程，定义了合理的扭转失稳临界风速，并评估了主缆竖向变形和侧向变形对主缆系统刚度退化及桥梁静风稳定性的影响。 （5）采用静力有限元法计算了在均匀流场中西堠门大桥的扭转发散临界风速和临界竖向位移，随后采用动力有限元方法计算了该桥在紊流场中的扭转发散临界风速和临界竖向位移，并运用第五章推导的理论知识来解释这些计算成果。 （6）对大跨度悬索桥的静风稳定性进行了参数分析，主要针对初始风攻角、主缆风荷载、紊流强度、紊流的空间相关性、材料非线性等因素进行探究并评价了这些因素对桥梁风致响应及其静风稳定性能的影响。
[Abstract]:In the past, the wind resistance of long-span suspension bridges was mainly focused on the dynamic instability and buffeting response of the structures. However, the phenomenon of static torsional divergence caused by the degradation of the stiffness of the main cable under wind load is not given equal attention. Wind tunnel tests and studies in recent years show that the static wind instability of long-span bridges is likely to occur along with the long refinement of bridges. Therefore, it is necessary to study the mechanism of static wind instability of long span suspension bridge. In this paper, based on the principle of harmonic synthesis, the fast simulation of random pulsating wind speed of long-span bridges is realized by using cubic uniform spline interpolation method based on the previous literatures. The static wind stability of long span suspension bridge in turbulent flow is solved by using dynamic finite element method. The mechanism of stiffness degradation and torsional divergence of long span suspension bridge is further improved. The effects of vertical and lateral deformation of main cable on torsional stiffness of main cable system are studied. Finally, the wind-induced response of long-span suspension bridge is analyzed. The main work of this paper is as follows: (1) the basic concept of static wind stability of long-span bridges is introduced, and the analysis theory of static wind stability of long-span bridges and its solution are summarized. (2) using harmonic synthesis method and cubic uniform spline interpolation method, the fast simulation of random pulsating wind speed of long-span bridges is realized. (3) the static wind buckling critical wind speed of long-span suspension bridge in uniform flow field is solved by the combination of load increment and internal and external double iteration (static finite element method) and dynamic finite element method (DFEM), respectively. The results show that the results obtained by the two methods are consistent. (4) based on the beam-cable generalized model, the generalized torsional stiffness expression of the main cable system is derived, the generalized motion equation of the system is established, and the reasonable critical wind speed of torsional instability is defined. The effects of vertical and lateral deformation of main cable on stiffness degradation of main cable system and static wind stability of bridge are evaluated. (5) the critical wind speed and the critical vertical displacement of the torsional divergence in the uniform flow field are calculated by using the static finite element method. Then the critical torsional divergence wind speed and critical vertical displacement of the bridge in turbulent flow field are calculated by using the dynamic finite element method, and these results are explained by using the theoretical knowledge derived in Chapter 5. (6) the static wind stability of the long-span suspension bridge is analyzed, which is mainly aimed at the initial wind attack angle, the wind load of the main cable, the turbulence intensity and the spatial correlation of turbulence. The influence of these factors on the wind-induced response and static wind stability of bridges was investigated and evaluated.
【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;U448.25
本文编号：2307884
[Abstract]:In the past, the wind resistance of long-span suspension bridges was mainly focused on the dynamic instability and buffeting response of the structures. However, the phenomenon of static torsional divergence caused by the degradation of the stiffness of the main cable under wind load is not given equal attention. Wind tunnel tests and studies in recent years show that the static wind instability of long-span bridges is likely to occur along with the long refinement of bridges. Therefore, it is necessary to study the mechanism of static wind instability of long span suspension bridge. In this paper, based on the principle of harmonic synthesis, the fast simulation of random pulsating wind speed of long-span bridges is realized by using cubic uniform spline interpolation method based on the previous literatures. The static wind stability of long span suspension bridge in turbulent flow is solved by using dynamic finite element method. The mechanism of stiffness degradation and torsional divergence of long span suspension bridge is further improved. The effects of vertical and lateral deformation of main cable on torsional stiffness of main cable system are studied. Finally, the wind-induced response of long-span suspension bridge is analyzed. The main work of this paper is as follows: (1) the basic concept of static wind stability of long-span bridges is introduced, and the analysis theory of static wind stability of long-span bridges and its solution are summarized. (2) using harmonic synthesis method and cubic uniform spline interpolation method, the fast simulation of random pulsating wind speed of long-span bridges is realized. (3) the static wind buckling critical wind speed of long-span suspension bridge in uniform flow field is solved by the combination of load increment and internal and external double iteration (static finite element method) and dynamic finite element method (DFEM), respectively. The results show that the results obtained by the two methods are consistent. (4) based on the beam-cable generalized model, the generalized torsional stiffness expression of the main cable system is derived, the generalized motion equation of the system is established, and the reasonable critical wind speed of torsional instability is defined. The effects of vertical and lateral deformation of main cable on stiffness degradation of main cable system and static wind stability of bridge are evaluated. (5) the critical wind speed and the critical vertical displacement of the torsional divergence in the uniform flow field are calculated by using the static finite element method. Then the critical torsional divergence wind speed and critical vertical displacement of the bridge in turbulent flow field are calculated by using the dynamic finite element method, and these results are explained by using the theoretical knowledge derived in Chapter 5. (6) the static wind stability of the long-span suspension bridge is analyzed, which is mainly aimed at the initial wind attack angle, the wind load of the main cable, the turbulence intensity and the spatial correlation of turbulence. The influence of these factors on the wind-induced response and static wind stability of bridges was investigated and evaluated.
【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;U448.25
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