板桁组合钢桁梁桥受力特性及整体节点细节构造分析

发布时间：2018-06-27 06:10

本文选题：板桁组合结构 + 整体节点　；参考：《兰州交通大学》2015年硕士论文

【摘要】：本文采用Midas Civil软件对双线铁路板桁组合钢桁梁桥建立了基于板梁混合单元的全桥空间有限元模型,研究分析了下承式简支钢桁梁桥在不同荷载工况下的受力特性。接着采用有限元软件Ansys Workbench从构造细节方面对整体节点的应力分布、高强螺栓预紧力损失、接触应力进行了较深入的分析。本文主要研究工作和成果如下:1、采用SPB板梁混合单元法并考虑刚域效应对板桁组合钢桁梁桥建立了全桥有限元模型,针对桥梁在不同工况(恒载、最不利活载、主力以及主力和附加力组合作用)下的受力特性进行了分析。计算分析结果表明:该桥整体受力合理,强度和刚度都符合铁路桥梁规范设计要求。2、对主桁下弦杆节点进行了主力荷载作用下的局部分析。计算结果表明:考虑高强螺栓时节点板的应力集中点数值比不考虑螺栓时小,在节点板圆弧部位、节点板与底板连接部位、节点板与纵肋相交处应力集中程度较高,等效应力较大,但未超过材料的屈服强度。3、对内外侧节点板上的高强螺栓预紧力损失进行了分析,解释了螺栓施拧时为何提高预拉力的原因,同时为不同位置的螺栓施拧提供了参考。4、从摩擦应力、挤压应力、滑移距离、渗透距离四个方面对接触面间应力状态进行了研究,得出了摩擦应力与挤压应力的分布规律;根据滑移距离判断出板束间产生了“解扣滑移”现象,使得节点板内力发生了重分布。5、通过约束端支反力与各杆件内力验算后,可得出以下结论:考虑高强度螺栓的局部分析模型很好的模拟了整体节点板的真实受力状态,与整体模型分析结果基本吻合,且反映出整体模型所不具有的应力集中、高强螺栓应力传递等现象。
[Abstract]:In this paper, Midas Civil software is used to establish the spatial finite element model of the whole bridge based on the plate and beam hybrid element for the composite steel truss bridge of double-track railway, and the stress characteristics of the through simply supported steel truss bridge under different load conditions are studied and analyzed. Then, the stress distribution of the whole joint, the loss of pretightening force of high strength bolt and the contact stress of the whole joint are analyzed in detail by the finite element software Ansys Workbench. In this paper, the main research work and results are as follows: 1. Using SPB slab beam hybrid element method and considering the rigid domain effect, the finite element model of the whole bridge is established, aiming at the bridge under different working conditions (dead load, most unfavorable live load). The force characteristics of the main force and the combination of the main force and the additional force are analyzed. The results of calculation and analysis show that the overall force of the bridge is reasonable and the strength and stiffness are in line with the design requirements of the railway bridge code. The local analysis of the chord joint under the main truss is carried out under the main force load. The results show that the stress concentration point of the joint plate is smaller when considering the high strength bolt than when the bolt is not taken into account, and the stress concentration is higher at the arc part of the joint plate, the connection between the joint plate and the bottom plate, and the intersection of the joint plate and the longitudinal rib. The equivalent stress is large, but does not exceed the yield strength of the material. The loss of pretension force of the high strength bolt on the inner and outer joint plate is analyzed, and the reason why the pretension force is increased when the bolt is twisted is explained. At the same time, it provides a reference for bolting in different positions. The stress state of contact plane is studied from four aspects: friction stress, extrusion stress, slip distance and penetration distance, and the distribution of friction stress and extrusion stress is obtained. According to the slip distance, the phenomenon of "unbuckling and sliding" occurred between the plates and bundles, which made the internal force of the joint plate redistribute .5.After checking the reaction force of the restrained end support and the internal force of each member, The following conclusions can be drawn: considering the local analysis model of high strength bolt, the real stress state of the whole joint plate is well simulated, which is basically consistent with the analysis result of the whole model, and reflects the stress concentration which the whole model does not have. High strength bolt stress transfer and other phenomena.
【学位授予单位】：兰州交通大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U441

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