Abstract: Taking the new double-welded of U-rib joint of steel bridge deck as the research object, the welding process of U-rib joint of steel bridge was simulated by finite element method, and the temperature field and residual stress field of U-rib weld and surrounding base metal were obtained by indirect coupling method. The differences of residual stress distribution between single welding and double welding were compared. The differences of residual stress peak and distribution caused by two different welding processes in the double side welding were discussed. Furthermore, the optimal temperature difference between layers was obtained by controlling the welding time interval of inner and outer fillet welds, which reduced the residual stress of welded joints. The results show that the longitudinal residual stress at the toe of double side welding is close to the yield strength of the base metal and will become a new fatigue hot spot. The greater residual stress will be generated when the inside and outside fillet welds of double-sided welding are welded simultaneously; therefore, keeping the welding process of internal welding firstly and external welding later is suggested. In a certain range of temperature difference, the distribution range of residual stress and peak stress of the welded joint and its surrounding thermal impact zone are positively correlated with the temperature difference between layers. Under the condition that the production schedule of U-rib remains unchanged, the residual stress of the roof obtained is relatively small when the temperature difference between layers is 100 ℃.

Key words: bridge engineering, steel bridge deck, welding, residual stress, numerical analysis

摘要： 以钢桥面板U肋接头新型双面焊为研究对象，通过有限元方法模拟了U肋的焊接过程，并采用间接耦合法得到了U肋焊缝及周围母材的焊后温度场及残余应力场。比较了单面焊与双面焊残余应力分布的差异；探讨了双面焊2种不同工艺造成残余应力峰值及分布的差异；并进一步通过控制内、外侧角焊缝的施焊时间间隔以获得最佳的层间温差，实现对焊缝接头残余应力的降低。结果表明：双面焊内焊缝焊趾处纵向残余应力接近母材屈服强度，将会成为新的疲劳热点；双面焊内外侧角焊缝同时施焊将会产生更大的残余应力，建议仍保持先内焊后外焊的焊接工艺；在一定的温差范围内，焊接接头及其周围热影响区残余应力分布范围及峰值应力与层间温差成正相关，在保证U肋制作进度不变的情况下，控制层间温差为100 ℃时得到的顶板残余应力较小。

关键词: 桥梁工程, 钢桥面板, 焊接, 残余应力, 数值分析