关键词: 桥梁工程, 钢桥面板, 焊接, 残余应力, 数值分析

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