铁路钢桥节点焊缝区域疲劳寿命评估与延寿控制的研究

发布时间：2018-04-23 05:28

本文选题：多尺度 + 残余应力　；参考：《武汉理工大学》2015年硕士论文

【摘要】：随着我国铁路运营里程的不断增长,大型铁路桥梁的建设量不断增加,多数铁路桥梁采用焊接钢结构型式,由于在列车行走的长期作用下,铁路钢桥节点焊缝区域累积疲劳损伤随时可能发生,疲劳破坏不同于一般的结构破坏,破坏前没有明显的塑性变形,一般性的检查难以发现也难以采取预防措施,是桥梁安全的重大威胁,因此铁路钢桥的疲劳尤其是焊缝区域的疲劳需要给予特别的重视。本文以铜九线鄱阳湖大桥为工程背景展开对铁路钢桥考虑焊接残余应力和列车过桥荷载共同作用下的疲劳裂纹萌生寿命评估和寿命控制的研究。根据对国内外现有的对铁路钢桥节点焊缝区域疲劳裂纹萌生寿命评估与寿命控制的研究现状分析,结合目前的研究的实际,本文主要对以下几个方面进行了研究:首先,本文介绍了相关的工程背景,采用基于子模型法的多尺度分析方法建立铁路钢桥的壳-实体多尺度有限元模型,对铁路钢桥考虑焊接残余应力和列车荷载共同作用下的响应进行分析,确定疲劳危险点。然后,采用适用于考虑焊接残余应力下铁路钢桥节点焊缝区域的基于临界面的多轴疲劳裂纹萌生寿命评估方法,对铜九线鄱阳湖大桥进行考虑焊接残余应力的铁路钢桥列车荷载作用下的裂纹萌生寿命评估。最后,本文将桥梁智能控制理论和方法应用于铁路钢桥的寿命控制,通过在铁路钢桥各跨跨中设置MR-TMD智能控制系统,使用编写的控制程序分析出粗糙的壳体全桥模型在精确节点边界处的位移时程响应,并通过子模型法将控制后的位移边界时程作用在精确实体模型上,获得控制后节点焊缝区域的精确应力状态,从而获得控制后的铁路钢桥节点焊缝区域的疲劳裂纹萌生寿命。综上所述,本文的研究将桥梁结构疲劳裂纹萌生寿命评估方法和智能控制理论有效结合,建立一套完整的列车行走作用下铁路钢桥节点焊缝区域疲劳裂纹萌生寿命评估方法和延长其寿命的智能控制的理论,对改善铁路钢桥的抗疲劳破坏能力、降低铁路钢桥维护成本方面和重特大事故的预防方面有一定的经济和社会效益。
[Abstract]:With the increasing mileage of railway operation in our country, the construction of large railway bridges is increasing. Most railway bridges adopt welded steel structure, because of the long-term action of train running, The cumulative fatigue damage may occur at any time in the weld zone of the joint of railway steel bridge. The fatigue damage is different from that of the normal structure. There is no obvious plastic deformation before the damage, and the general inspection is difficult to find and take preventive measures. It is a great threat to bridge safety, so the fatigue of railway steel bridge, especially the fatigue of weld zone, should be paid more attention. In this paper, the fatigue crack initiation life evaluation and life control of the railway steel bridge under the joint action of welding residual stress and train crossing load are carried out under the engineering background of Poyang Lake Bridge of Tongjiu Line. Based on the analysis of the current research situation of fatigue crack initiation life assessment and life control in the weld zone of railway steel bridge joints at home and abroad, combined with the current research practice, this paper mainly studies the following aspects: first, In this paper, the engineering background is introduced, and the multi-scale finite element model of the steel bridge is established by using the multi-scale analysis method based on the sub-model method. The response of railway steel bridge under the joint action of welding residual stress and train load is analyzed to determine the fatigue danger point. Then, a multiaxial fatigue crack initiation life evaluation method based on the interface is adopted, which is suitable for the weld zone of the joint of railway steel bridge considering the welding residual stress. The crack initiation life of the railway steel bridge under train load considering welding residual stress was evaluated for Poyang Lake Bridge of Tongjiu Line. Finally, this paper applies the theory and method of bridge intelligent control to the life control of railway steel bridge. By setting up MR-TMD intelligent control system in each span of railway steel bridge, The displacement-time history response of the rough shell full-bridge model at the precise node boundary is analyzed by using the control program, and the controlled displacement boundary time-history is acted on the precise entity model by the submodel method. The precise stress state of the weld zone after the control is obtained, and the fatigue crack initiation life of the welded joint area of the railway steel bridge after the control is obtained. To sum up, this paper combines the fatigue crack initiation life evaluation method of bridge structure and intelligent control theory effectively. A set of complete evaluation methods of fatigue crack initiation life and intelligent control theory of fatigue crack initiation in weld zone of railway steel bridge joint under the action of train running are established, which can improve the fatigue failure resistance of railway steel bridge. It has certain economic and social benefits to reduce the maintenance cost of railway steel bridges and to prevent serious accidents.
【学位授予单位】：武汉理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U441.4

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