钢箱梁横隔板焊缝疲劳性能的锤击效果研究

王秋东 吉伯海 傅中秋 袁周致远

摘 要：针对钢箱梁横隔板与U肋连接焊缝疲劳细节，选取了三个局部试件作为研究对象，采用锤击装置对试件弧形缺口处焊缝的焊趾部位进行锤击处理，并采用疲劳试验机对处理后试件进行疲劳加载，对比分析试件的疲劳裂纹扩展情况、疲劳应力幅和疲劳强度的变化情况。同时，建立了局部锤击有限元模型，分析锤击部位的残余应力、塑性变形等，并结合疲劳试验结果，从疲劳裂纹萌生寿命、疲劳强度、锤击残余应力分布等角度，对锤击效果进行了评价。研究结果表明，锤击处理可有效提高横隔板与U肋连接焊缝的疲劳裂纹萌生寿命及疲劳强度；锤击处理可产生明显的塑性变形及残余应力，且两者均以焊趾为中心近似呈圆弧状分布；锤击深度为0.2mm时，锤击残余压应力沿板厚、垂直焊缝方向的分布范围均为3mm左右，从而改善构件的疲劳性能。

关键词：钢箱梁；疲劳性能；锤击；裂纹萌生寿命；残余压应力

中图分类号： U44332 文献标志码：A

文章编号：1672-1098（2017）06-0015-06

Abstract：Based on the fatigue details of diaphragm-to-rib weld joints in steel box girder， three local specimens were selected as the objects. Hammer peening equipment was adopted to conduct peening processing in weld toe nearby the arc gap of specimens and fatigue tests of specimens were conducted by fatigue test machine afterwards. The propagation of fatigue cracks， fatigue stress amplitude and fatigue resistance were compared and analyzed after fatigue test. Meanwhile， finite element model of local hammer peening was established to analyze the residual stress and plastic deformation in the peening area. Combined with the fatigue test results， the peening effects were evaluated from the point of initiation life of fatigue cracks， fatigue resistance of specimens and distribution of residual stress. The analysis results show that the cracks initiation life and fatigue resistance of diaphragm-to-rib weld joint could be enhanced effectively. Obvious plastic deformation and residual stress could be produced by hammer peening and both be distributed as arc shape approximately center in the weld toe. The distribution range of residual compressive stress along the thickness of plate and vertical to the weld were both around 3mm at the hammer depth of 0.2mm， which could help to improve the fatigue performance of specimens.

Key words：steel box girder； fatigue performance； hammer peening； cracks initiation life； residual compressive stress

扁平流线型钢箱梁因具有自重轻、稳定性好、承载力高、制作施工便捷等优点，在大跨径缆索体系桥梁中得到了广泛运用[1-2]。但是钢箱梁构造复杂，各构件多采用焊接连接，焊接过程中易产生较大的残余应力，加上其他不利因素的影响，在使用过程中难免会产生损伤[3-4]。随着桥梁服役年限的增加，钢箱梁逐渐产生各种病害，其中疲劳病害尤为突出[5-6]。疲劳裂纹不可避免，检测、维修困难，且在维护过程中易产生二次缺陷，造成新的損伤[7]。……