轮迹位置对钢桥面板U肋对接焊缝疲劳性能的影响

Fatigue influence for wheels position of the orthotropic steel bridge deck of U-rib butt weld

为研究车轮行驶位置对钢桥面板U肋对接焊缝疲劳性能的影响,现以江阴长江大桥为研究对象,采用数值模拟的方法,计算了不同车辆轮迹位置作用下U肋对接焊缝处的疲劳应力幅,结合BS5400规范得到了该细节相应位置的疲劳损伤度;建立U肋对接焊缝局部模型,模拟了不同车轮位置作用下疲劳裂纹扩展路径,同时得到了各扩展阶段的裂纹扩展参数。结果表明:车轮位置与焊缝之间距离大于600 mm,可忽略车辆位置对U肋对接焊缝开裂前的疲劳损伤累计;相对于其他部位,U肋两侧弧形段疲劳损伤严重,易产生疲劳裂纹;随着车轮位置的改变,裂纹扩展路径逐渐由与焊缝平行向与焊缝垂直发展,车轮位置与焊缝之间距离大于750 mm,可忽略车辆位置对U肋对接焊缝开裂后的裂纹扩展影响。

In order to study the fatigue effect of the orthotropic steel bridge deck of U-rib butt weld under different wheels position, which use the numerical simulation method and as the Jiangyin Yangtze River Bridge for research object. First use the general-purpose finite element software to analysis the fatigue stress amplitude of U-rib butt welds under different wheels position, which com-bined with BS5400 standard to calculate the degree of fatigue damage for this fatigue details, and then use FRANC2 D/L software to simulate the changing rules of crack propagation path under differ-ent wheels positions. The results show that： the distance of wheels and U-rib is greater than 600 mm, it can ignore the fatigue damage cumulative to butt weld; compared to other sites, the fatigue damage of the sides of U-rib arc-shaped segment is serious, which easy to produce fatigue crack;with the change of the position of the wheels, the crack propagation path change from parallel to the butt weld to the vertical to the butt weld gradually, and while the distance of wheels and U-rib＆amp;nbsp;is greater than 750mm, the effect of wheels position to crack propagation can be ignored.