Welded steel structure is widely used in the bridge engineering ,but the welded joints lead to fatigue problems easily due to welding residual stress generated inevitably in the welding process .It is difficult to consider the real value of welding residual stress in the detailed classification of current specifications .Based on the Goodman formula and empirical theory ,the S-N curve of material was modified by considering the welding residual stress quantitatively ,and the S-N curve for welding joints was obtained .In this paper ,welded detail with cope hole in truss oblique rod of the bridge gird-er is introduced as an example to demonstrate the detailed steps .With the analysis of coupled thermo-mechanical model ,the numerical simulation of welding residual stress was conducted .In addition ,the stress concentration factor was obtained by using extrapolation methods for hot spot stress .With the proposed method ,the S-N curve of the welded detail with cope hole was determined ,which can pro-vide a guidance for accurately predicting the fatigue life and anti-fatigue design .%焊接钢结构在桥梁中广泛应用,在焊接过程中不可避免的会产生焊接残余应力,使焊接部位易引发疲劳问题,而现行规范中的细节分类不能反映实际焊接残余应力水平.基于Goodman公式及相关经验理论,提出定量考虑焊接残余应力来修正材料S-N曲线,从而确定构造细节S-N曲线的方法,并验证了其可行性.以钢桁梁斜腹杆过焊孔构造细节为分析实例,采用热-结构耦合的分析方法对其焊接残余应力进行了数值模拟分析,并利用热点应力外推法对其应力集中效应进行了有限元计算,根据所提方法,得到了过焊孔构造细节S-N曲线,为准确评估结构疲劳寿命和抗疲劳设计提供指导.
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