采用数值计算方法对圆形焊接钢管的弯曲性能进行研究。用有限元(FE)法模拟环缝的焊接过程,采用三维(3D)热力耦合FE模型得到焊接残余应力和变形。结合焊接引起的几何缺陷和残余应力,对焊接圆钢管的失效模式、抗弯承载能力以及纯弯曲状态下的端部扭转性能进行了弹塑性大变形分析。结果表明,圆形焊接钢管的弯曲性能包含邻近焊缝处受压区的局部屈曲,这对端部扭矩有着显著影响。 The bending behavior of circular welded steel pipe is studied by numerical method. Finite element (FE) method was used to simulate the welding process of girth weld, and the welding residual stress and deformation were obtained by using three-dimensional (3D) thermodynamic coupled FE model. Combined with the geometric defects and residual stresses caused by welding, the large-scale elasto-plastic deformation analysis of the failure mode, flexural capacity and torsional behavior of the welded round steel tube under pure bending condition were carried out. The results show that the bending behavior of round welded steel pipe includes the local buckling of the compression zone near the weld, which has a significant effect on the torque at the tip.