铁路刚架系杆拱桥销铰式锚固结构疲劳性能研究

发布时间：2018-05-11 22:14

本文选题：销铰式锚固结构 + 模型试验　；参考：《西南交通大学》2017年硕士论文

【摘要】：在钢桥中,索梁锚固结构是影响桥梁安全使用的关键位置,通常具有结构复杂、应力集中、焊缝密集等特点,其疲劳性能很难被设计人员所把握。本文基于以上背景,对拱桥销铰式锚固结构疲劳性能进行研究。以广州枢纽跨桂丹路(24+160+24)m钢管混凝土刚架系杆拱连续箱梁组合桥1#桥作为工程背景,采用模型试验与有限元理论分析相结合的方式,对其销铰式锚固结构的疲劳性能进行研究。主要研究内容及结论如下:(1)建立有限元模型,选取吊杆力幅值最大的锚固区梁段,对设计荷载下锚固区的整体应力分布及索力在焊缝内部的分配规律进行了分析,同时对销铰连接的力学特性进行了接触非线性分析。结果表明,锚固结构局部存在应力集中现象,索力的传递较为流畅,耳板-桥面板、耳板-横隔板、耳板-桥面加劲板三条焊缝承担了 80%的索力,但在焊缝内部应力分布很不均匀。(2)根据列车实际运行计划,结合Palmgren-Miner线性疲劳累计损伤准则确定了疲劳荷载。设计了 1:2缩尺试验模型对销铰式索梁锚固结构的疲劳性能展开试验研究。260万次循环加载后使用磁粉及超声波对试验模型进行了探伤检查未发现裂纹,各测点应力测试结果波动不大且加载卸载曲线呈线性变化,并根据规范对结构的疲劳应力进行了验算。试验及验算结果证明了销铰式索梁锚固结构抗疲劳性能良好且具有一定的疲劳安全储备。(3)采用扩展有限元法对该拱桥销铰式锚固结构的关键构造细节进行了三维裂纹扩展仿真,分析了裂纹扩展过程中裂纹扩展速率及应力强度因子的变化规律,并依据Paris公式对该销铰式锚固结构的疲劳寿命进行了初步预测。
[Abstract]:In steel bridges, cable girder Anchorage structure is the key position affecting the safety of bridges. It usually has the characteristics of complex structure, stress concentration and welding seam density, so its fatigue performance is difficult to be grasped by designers. Based on the above background, the fatigue behavior of pin-hinged Anchorage structure of arch bridge is studied in this paper. Taking the concrete filled steel tube concrete continuous box girder composite bridge which spans Guidan Road in Guangzhou as the engineering background, the model test is combined with the finite element theory analysis. The fatigue behavior of pin-hinged Anchorage structure is studied. The main research contents and conclusions are as follows: (1) establish the finite element model, select the beam section of anchoring zone with the largest amplitude of the suspender force, and analyze the overall stress distribution of the anchoring zone and the distribution law of cable force in the weld seam under the design load. At the same time, the contact nonlinear analysis of the mechanical properties of pin-hinge connection is carried out. The results show that the local stress concentration exists in the Anchorage structure, and the transfer of cable force is relatively smooth. The three welds of ear slab-bridge slab, ear-slab-transverse partition, ear-slab-bridge stiffener bear 80% cable force. However, the stress distribution in the weld is very uneven. (2) according to the actual operation plan of the train, combined with the Palmgren-Miner linear fatigue cumulative damage criterion, the fatigue load is determined. A 1:2 scale test model was designed to test the fatigue behavior of the pin-hinged cable beam Anchorage structure. After 2.6 million cycles of loading, no cracks were found in the model by using magnetic powder and ultrasonic wave. The stress test results of each measuring point are not fluctuant and the loading and unloading curves are linearly changed, and the fatigue stress of the structure is checked and calculated according to the code. The results of test and calculation prove that the anti-fatigue performance of the pin-hinged cable beam Anchorage structure is good and has certain fatigue safety reserve. The expanded finite element method is used to simulate the three dimensional crack growth of the key structure of the pin hinged anchor structure of the arch bridge. The variation of crack growth rate and stress intensity factor during crack growth is analyzed, and the fatigue life of the pin hinged Anchorage structure is preliminarily predicted according to Paris formula.
【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;U448.225

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