宽幅钢箱梁环焊缝焊接顺序优化研究

基于热弹塑性有限元法,采用ANSYS软件建立了网格疏密过渡的单箱五室钢箱梁壳单元模型;结合高效的分段移动热源,实现了对大型复杂长焊缝结构焊接全过程的数值模拟,并定性对比了宽幅钢箱梁在不同的环焊缝焊接顺序下顶板和底板的变形情况。分析结果表明:腹板焊缝的焊接顺序对竖向最大变形值(绝对值)的影响不大,其值主要取决于顶板和底板的焊接顺序;顶板和底板沿焊缝方向将会产生明显的"波浪变形",且整体外翘;中室所对应的顶板和底板沿焊缝方向的变形分别呈现出"M"形和"W"形;在垂直于焊缝的路径上,随着距焊缝中心线距离的增大,竖向变形整体减小;采用一定的焊接顺序,可有效调整钢箱梁顶板和底板焊缝附近"波浪变形"的变化幅度。以钢箱梁顶板焊缝中心线的线形为比选标准,确定的最优焊接顺序为先从外到内焊接腹板对接焊缝,再依次焊接顶板和底板对接焊缝。

Study on the welding sequence optimization of circumferential welds of wide steel box girder

Based on the thermal elastic-plastic finite element method, a finite element model of steel single girder with single-box five-cells is established by ANSYS software. The model adopts shell element and non-uniform mesh generation method. The whole welding process of large complex structure with long weld is numerically simulated by using efficient segmented moving heat source, and the deformation of top and bottom plates of wide steel box girder under different welding sequence of circumferential welds is qualitatively compared. The results show that the welding sequence of web’s welds has little effect on the maximum vertical deformation(absolute value), it mainly depends on the welding sequence of the top and bottom plates. There will be obvious "wave deformation" along the weld direction on the top and bottom plates and overall outwarping deformation. The deformation of the top and bottom plates corresponding to the middle chamber along the weld direction is relatively gentle, showing "M" and "W" shapes respectively. On the path perpendicular to the weld seam, the vertical deformation decreases with the increase of distance between measuring point and weld seam. With a certain welding sequence, the variation range of "wave deformation" of the top and bottom plates of steel box girder can be adjusted effectively. A certain welding sequence can effectively adjust the variation range of "wave deformation" near the weld seam of the roof and floor of the steel box girder. Taking the alignment of the weld center line of the top plate of steel box girder as the comparison criterion, the optimal welding sequence is to weld the butt weld of web from outside to inside firstly, and then weld the butt weld of top and bottom plates.