基于断裂力学的钢桥面肋-板接头疲劳寿命预测

发布时间：2018-01-25 08:34

本文关键词： 正交异性钢桥面焊接细节疲劳寿命断裂力学应力强度因子　出处：《西南交通大学学报》2017年01期 　论文类型：期刊论文

【摘要】：为研究反复荷载作用下正交异性钢桥面中U型肋与桥面板焊接接头的疲劳性能,基于断裂力学基本理论,利用有限元方法,进行了肋-板接头的疲劳寿命评估.根据正交异性钢桥面与U型肋连接构造基本形式,利用有限元软件ANSYS建立了包含3个U型肋的正交异性钢桥面平面有限元模型;考虑肋-板连接位置处焊接细节的4种典型裂纹,计算了2个加载工况下各裂纹处等效应力强度因子,并分析了初始裂纹长度、桥面板厚度、U型肋高度和U型肋厚度对等效应力强度因子的影响规律;依据Eurocode 3规范中正交异性钢桥面肋-板接头加载模式,采用桥面板与U型肋连接构造二维有限元模型,计算得到典型裂纹的等效应力强度因子,建立了基于断裂力学疲劳扩展模型为基础的正交异性钢桥面肋-板接头的疲劳寿命预测方法.研究结果表明:基于线弹性断裂力学原理计算得到的疲劳寿命均大于Eurocode 3规范计算值,桥面板厚度选用16~18 mm及将初始裂纹长度控制在0.1 mm以下可有效地提高板-肋接头疲劳寿命.
[Abstract]:In order to study the fatigue behavior of welded joints between U-rib and deck in orthotropic steel deck under repeated loading, the finite element method is used based on the basic theory of fracture mechanics. The fatigue life of rib-plate joint is evaluated. The basic form of the connection between orthotropic steel bridge deck and U-shaped rib is presented. The plane finite element model of orthotropic steel bridge deck with three U-shaped ribs is established by using finite element software ANSYS. The equivalent stress intensity factors at each crack under two loading conditions are calculated considering four typical cracks in the welding details at the rib-plate connection position. The initial crack length and the bridge slab thickness are analyzed. The influence of U-shaped rib height and U-shaped rib thickness on the equivalent stress intensity factor; According to the loading mode of orthotropic steel deck rib-plate joint in Eurocode 3 code, a two-dimensional finite element model is constructed by connecting deck slab with U-shaped rib. The equivalent stress intensity factor of a typical crack is calculated. A fatigue life prediction method for orthotropic steel bridge deck rib-plate joints based on fatigue propagation model of fracture mechanics is established. The results show that:. The fatigue life calculated by the principle of linear elastic fracture mechanics is larger than that of Eurocode 3 code. The fatigue life of slab-ribbed joints can be effectively improved by using 16mm thickness of deck slab and controlling the initial crack length below 0.1 mm.
【作者单位】：西南交通大学土木工程学院;中铁工程设计咨询集团有限公司济南设计院;
【基金】：国家自然科学基金资助项目(51378431)
【分类号】：U441.4
【正文快照】： 南250022)正交异性钢桥面自20世纪30年代问世以来,因承载能力强、自重轻、梁高低、制造方便等优点,已在国内外钢桥中大量使用.正交异性钢桥面由桥面板和相互垂直的纵、横向加劲肋组成,结构复杂,焊缝交错,既作为主梁的一部分共同参与受力,也要直接承受车轮荷载作用,部分焊接细

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