连续钢桁拱主桁节点和悬臂托架连接疲劳性能研究

发布时间：2018-05-15 23:07

本文选题：悬臂托架 + 应力谱　；参考：《西南交通大学》2017年硕士论文

【摘要】：钢桁架梁桥采用焊接连接较为普遍,焊接部位受力较为复杂。然而,焊接部位因受力复杂、应力集中等为题导致其疲劳问题突出。随着钢结构桥梁的跨度以及车辆荷载的不断增加,特殊部位的疲劳问题更为突出,给钢结构桥梁的运营和维护带来安全隐患。本文以南京大胜关大桥为工程背景,研究主梁与外侧悬臂梁焊接部位。钢桁架梁桥主梁与外侧悬臂梁连接部位应力梯度较大,疲劳失效常起始于此。本文依托该项目进行轻轨焊接悬臂托架疲劳试验,进行了疲劳试验模型的设计和验证。主要研究内容如下:1、介绍了目前国内外钢结构疲劳性能研究的背景和现状,总结钢结构疲劳性能研究的重点和方法。在总结已有研究成果的基础上,确定了本文的研究思路。2、详细阐述了疲劳破坏模式和断口特征,为疲劳破坏模式的判断提供参考;介绍了疲劳荷载谱的计算方法,以及将实际的变幅疲劳荷载谱转化为试验和计算的常福荷载谱的方法。在此基础上对几种疲劳累积损伤理论进行了对比分析,认为目前数据比较缺乏的情况下,线性累积损伤理论将是比较好的选择。3、根据车辆运营情况,确定疲劳破坏的关键区域。考虑费用和场地限值以及受力部位的要求,本模型为钢桁架局部缩尺模型。本文依据荷载和边界条件,限制关键部位的应力和位移。通过方案比选的方法,确定了疲劳试验的模型并开展相关试验。4、通过试验分析了悬臂结构在荷疲劳荷载作用下,应变和应力随荷载的变化情况。
[Abstract]:Welding connection is widely used in steel truss girder bridge, and the welding position is more complicated. However, the fatigue problem of welding site is prominent due to its complicated stress and stress concentration. With the continuous increase of span and vehicle load of steel bridge, the fatigue problem of special part is more prominent, which brings safety hidden trouble to the operation and maintenance of steel structure bridge. In this paper, the welding position between the main beam and the outer cantilever beam is studied with the background of Nanjing Dashengguan Bridge. The stress gradient of the connection between the main beam and the outer cantilever beam of the steel truss girder bridge is large, and the fatigue failure often begins at this point. In this paper, the fatigue test of light rail welding cantilever bracket is carried out, and the fatigue test model is designed and verified. The main research contents are as follows: 1. The research background and present situation of fatigue properties of steel structures at home and abroad are introduced, and the key points and methods of research on fatigue properties of steel structures are summarized. On the basis of summing up the existing research results, this paper determines the research ideas of this paper, expounds the fatigue failure mode and fracture characteristics in detail, provides a reference for the judgment of fatigue failure mode, and introduces the calculation method of fatigue load spectrum. And the method of converting the actual fatigue load spectrum of variable amplitude into the normal load spectrum of test and calculation. On this basis, several fatigue cumulative damage theories are compared and analyzed. It is concluded that linear cumulative damage theory will be a better choice under the condition of lack of data at present, and the key area of fatigue damage will be determined according to the vehicle operation situation. This model is a local scale model of steel truss, considering the cost, site limit and the requirement of force position. According to the load and boundary condition, the stress and displacement of the key position are limited. The model of fatigue test was established by the method of scheme comparison and the related test was carried out. The variation of strain and stress of cantilever structure with load under fatigue load was analyzed by experiment.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U441.4

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