低匹配对接接头形状参数对三点弯曲应力集中系数的影响

弹性阶段以提高低匹配接头弯曲承载能力为目标,基于有限单元法针对X形坡口低匹配对接接头三点弯曲形状设计,从材料力学方法角度出发,考察了双侧余高对称时低匹配对接接头的焊缝余高、盖面焊道宽度、焊趾过渡圆弧半径等形状参数对三个危险区弯曲应力集中系数的影响.结果表明,对母材与焊缝交界处突变区与焊缝底部中心区的影响规律为焊缝余高影响最大,盖面焊道宽度影响次之,焊趾圆弧半径影响最小；对焊趾部位影响规律为盖面焊道宽度的影响较大,焊趾圆弧半径和焊缝余高影响均较小.选择合适的形状参数可以提高低匹配接头弯曲承载能力.

Influence of joint geometric parameters on stress concentration factor for under-matched butt joint under three-point bending load

In order to improve the bending load-carrying capacity (BLCC) for under-matched butt joints in the elastic stage,the influence of joint geometric parameters on bending stress concentration factor (BSCF) for under-matched butt joint with X-type groove and double side symmetrical type reinforcement was studied based on the finite element method from the viewpoint of materials mechanics. The influence rules of joint geometric parameters on BSCF at the geometric mutations area near fusion line and in the weld bottom center show that the reinforcement plays the most important role in BSCF,the cover pass width has relatively great effect on BSCF and the weld toe radius has minimal effect on BSCF. The influence rules of joint geometric parameters on BSCF at the weld toe show that the cover pass width has some influence on BSCF,the reinforcement and the weld toe radius both have little influence on BSCF. BLCC of under-matched butt joint can be improved by choosing appropriate joint geometric parameters.