| 钢桥面板纵肋顶板焊缝疲劳裂纹扩展的关键影响因素 |
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| 引用本文： | 卜一之,金正凯,黄云,张清华,徐恭义.钢桥面板纵肋顶板焊缝疲劳裂纹扩展的关键影响因素[J].中国公路学报,2019,32(9):61-70. |
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| 作者姓名： | 卜一之 金正凯 黄云 张清华 徐恭义 |
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| 作者单位： | 1. 西南交通大学 土木工程学院, 四川 成都 610031;2. 中铁工程设计咨询集团有限公司, 北京 100055;3. 中铁大桥勘测设计院集团有限公司, 湖北 武汉 430050 |
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| 基金项目： | 国家自然科学基金项目（51978579，51778533，51578455，51378431，51178394）；"十二五"国家科技支撑计划项目（2011BAG07B03）；湖北省交通运输厅科技项目（2017-538-2-4）；中央高校基本科研业务费专项资金项目（2682014CX078） |
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| 摘 要： | 正交异性钢桥面板疲劳问题突出，纵肋与顶板焊缝处是其关键疲劳易损部位，研究该部位疲劳裂纹的扩展过程并确定关键影响因素及其效应，有助于深刻理解其疲劳损伤机理。建立正交异性钢桥面板疲劳试验节段模型的有限元分析模型，将纵肋与顶板焊缝焊根处的疲劳裂纹近似为半椭圆形裂纹，基于断裂力学实现其扩展全过程的三维数值模拟。在此基础上研究初始裂纹的纵向位置和初始裂纹形状对疲劳裂纹扩展过程的影响，阐明扩展过程中的疲劳裂纹的形状变化，以及疲劳裂纹关键部位应力强度因子幅值的变化规律。研究表明：对于典型的正交异性钢桥面板纵肋与顶板焊缝，在纵向一段范围内，初始裂纹的纵向位置对裂纹扩展的影响不大；初始裂纹形状对裂纹扩展的影响主要体现在裂纹扩展的初始阶段，经过一段时间的扩展之后，不同形状的初始裂纹将演变为相对稳定的形状；持续一段时间后，裂纹将逐渐变得较为扁长；疲劳裂纹在深度方向上扩展超过约顶板厚度一半时，最深点的扩展速率将会减慢；深度相同的裂纹，形状越扁长时越倾向于向深度方向扩展，越不扁长时越倾向于向长度方向扩展。
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| 关 键 词： | 桥梁工程 正交异性钢桥面板 断裂力学 纵肋与顶板焊缝 疲劳裂纹扩展 影响因素 |
| 收稿时间： | 2018-04-17 |
Key Influencing Factors of Fatigue Crack Propagation in Rib-to-deck Welded Joints of Orthotropic Steel Bridge Deck |
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| BU Yi-zhi,JIN Zheng-kai,HUANG Yun,ZHANG Qing-hua,XU Gong-yi.Key Influencing Factors of Fatigue Crack Propagation in Rib-to-deck Welded Joints of Orthotropic Steel Bridge Deck[J].China Journal of Highway and Transport,2019,32(9):61-70. |
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| Authors: | BU Yi-zhi JIN Zheng-kai HUANG Yun ZHANG Qing-hua XU Gong-yi |
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| Affiliation: | 1. School of Civil Engineering, Southwest Jiaotong University, Chengdu 610031, Sichuan, China;2. China Railway Engineering Consulting Group Co., Ltd., Beijing 100055, China;3. China Railway Major Bridge Reconnaissance & Design Institute Co., Ltd., Wuhan 430050, Hubei, China |
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| Abstract: | Orthotropic steel bridge decks generally suffer severe fatigue problems. Rib-to-deck welded joints are typical parts of the orthotropic steel bridge deck that are vulnerable to fatigue. Studying the fatigue crack propagation in rib-to-deck welded joints and identifying the key influencing factors that affect crack propagation are helpful for understanding the mechanisms of fatigue damage. A finite element model was established for an orthotropic steel bridge deck fatigue experiment model. The fatigue cracks at the weld root of the rib-to-deck welded joints were simplified to a semi-elliptical crack to enable continuous 3D simulations of the propagation process based on fracture mechanics. On this basis, the influences of the initial crack location and initial crack shape on the fatigue crack propagation process were studied. Further, the fatigue crack shape change during propagation and stress intensity factor range variations of the relevant points of the fatigue crack were explored. The research shows that for typical rib-to-deck welded joints of orthotropic steel bridge decks, the longitudinal location of the initial crack has little effect on the crack propagation within a certain distance. The effect of initial crack shape on the crack propagation is mainly reflected in the initial stage of crack propagation. The shapes of different initial cracks stabilize after a finite period of propagation. Once the shape is maintained for a certain period of time, the crack will gradually flatten. When the depth of the fatigue crack is more than approximately half the thickness of the deck, the propagation rate of the deepest point decreases. When the depth is in the same value, more flat crack tend to propagate in the depth direction, while less flat crack tend to propagate in the length direction. |
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| Keywords: | bridge engineering orthotropic steel bridge deck fracture mechanics rib-to-deck welded joint fatigue crack propagation influencing factors |
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