正交异性钢桥面板疲劳裂纹扩展过程数值模拟及其修复方法研究

发布时间：2018-03-12 06:36

本文选题：正交异性钢桥面板　切入点：等效应力幅　出处：《天津大学》2014年硕士论文　论文类型：学位论文

【摘要】：正交异性钢桥板凭借其承载能力大、自重轻、施工快和结构美观等优点，很好的解决了桥梁的自重、承重和跨径之间的矛盾，已经成为大跨径钢桥的首选桥面形式。对于正交异性钢桥面板来说，由于其不但要承受其顶部车辆的循环作用，而且作为主梁的一部分共同参与受力，从而造成局部承受的应力循环次数过多，且在梁体焊接过程中会引起不可避免的应力集中及焊接缺陷，，使得钢桥面板在运营一段时间后，极易产生疲劳裂纹。大跨度钢桥一旦出现疲劳裂纹，不仅维修困难、费用昂贵，而且会引起桥梁突然破坏的灾难性事故。目前疲劳开裂导致其维修加固需求十分突出，而一些维修加固的方法并不是十分有效，主要是对其疲劳失效机理的研究尚不深入。为了追踪正交异性钢桥面板的疲劳裂纹扩展过程，为通用的正交异性板的钢桥的抗疲劳设计和开裂加固提供理论指导，本文提出了基于实桥有限元模型进行正交异性钢桥面板疲劳裂纹扩展模拟的方法和流程，并对国内外钢桥裂纹修复方法进行了分类汇总。具体研究内容及成果如下： 1、提出了考虑疲劳荷载模型、车辆轮轴横向分布、平均日交通量、交通量年增长率、冲击系数等多种因素影响下，桥面板中各部位等效应力幅的计算方法，从而得到了更接近实际的等效应力幅计算公式。 2、提出了一种基于通用有限元软件的钢桥面板疲劳裂纹扩展过程数值模拟方法。首先，建立桥梁整体有限元模型，进行恒载及活载作用下的整体分析，并结合实桥调查结果确定全桥疲劳关键部位；然后，建立包含焊接细节的疲劳关键部位的精细化模型进行疲劳应力幅分析，同时基于车桥耦合振动分析考虑冲击系数对应力幅的影响，确定裂纹扩展方向、路径及寿命，进行疲劳裂纹扩展全过程分析。 3、以某既有大跨度桥梁的钢桥面板疲劳裂纹扩展为例，验证了本文方法和计算流程的可行性、计算结果的准确性，研究了桥面铺装层、路况、车辆超载及交通量年增长率等因素对疲劳裂纹扩展寿命的影响，并为该桥运营期疲劳失效维修与加固提供了理论依据。 4、对正交异性钢桥面板疲劳裂纹修复方法进行了汇总分析，研究成果可为各个疲劳细节部位维修加固方案的制定提供参考。
[Abstract]:The orthotropic steel bridge plate has the advantages of large bearing capacity, light weight, fast construction and beautiful structure, which solves the contradiction between the weight, bearing capacity and span of the bridge. It has become the preferred deck form for long span steel bridges. For orthotropic steel bridge panels, they not only bear the cyclic action of their top vehicles, but also participate in the force as part of the main beam. As a result, the number of local stress cycles is excessive, and the inevitable stress concentration and welding defects will be caused in the welding process of the beam body, which makes the steel bridge face plate operate for a period of time. It is easy to produce fatigue crack. Once there are fatigue cracks in long span steel bridge, it is not only difficult to maintain and expensive, but also can cause the catastrophic accident of bridge sudden destruction. At present, fatigue cracking causes the demand for maintenance and reinforcement to be very prominent. However, some methods of maintenance and reinforcement are not very effective, and the research on fatigue failure mechanism is not deep. In order to track the fatigue crack propagation process of orthotropic steel bridge panel and provide theoretical guidance for fatigue design and crack strengthening of orthotropic steel bridge. In this paper, the method and flow of fatigue crack propagation simulation of orthotropic steel bridge slab based on the finite element model of real bridge are put forward, and the crack repairing methods of steel bridge at home and abroad are classified and summarized. The concrete research contents and results are as follows:. 1. Under the influence of fatigue load model, lateral distribution of vehicle wheel axle, average daily traffic volume, annual growth rate of traffic volume, impact coefficient and other factors, the equivalent stress amplitude of each part of bridge deck is calculated. A formula for calculating the equivalent stress amplitude is obtained, which is closer to the actual situation. 2. A numerical simulation method for fatigue crack propagation process of steel bridge face slab based on universal finite element software is proposed. Firstly, the integral finite element model of the bridge is established, and the whole analysis under dead load and live load is carried out. Combined with the investigation results of the real bridge, the key parts of fatigue of the whole bridge are determined, and then, the fatigue stress amplitude analysis is carried out by establishing a fine model of the key parts of fatigue including welding details, and analyzing the fatigue stress amplitude of the whole bridge. At the same time, based on the vehicle-bridge coupling vibration analysis, considering the impact coefficient on the stress amplitude, the crack propagation direction, path and life are determined, and the whole process of fatigue crack growth is analyzed. 3. Taking the fatigue crack propagation of a steel bridge slab of an existing large-span bridge as an example, the feasibility and accuracy of the method and calculation flow are verified, and the pavement and road conditions of the bridge deck are studied. The influence of vehicle overload and annual growth rate of traffic volume on fatigue crack propagation life is also discussed, which provides a theoretical basis for fatigue failure maintenance and reinforcement of the bridge during operation period. 4. The fatigue crack repair methods of orthotropic steel bridge face are summarized and analyzed, and the research results can be used as a reference for the establishment of maintenance and reinforcement schemes for various fatigue detail parts.
【学位授予单位】：天津大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U448.36;U441

【相似文献】