不锈钢车体激光焊连接的模拟方法及强度评估

Simulation Method and Strength Evaluation of Laser Welding Connection of Stainless Steel Car Body

采用有限元分析方法研究不锈钢车体侧墙激光焊连接的模拟方法与强度分析问题。首先,分别建立实体单元、薄壳单元及梁单元模拟半熔透搭接激光焊连接强度的分析模型,以及梁单元模拟不同焊缝长度的分析模型,并在相同计算条件下,通过对比分析确定了适用于复杂结构激光焊连接强度分析的焊缝单元类型;其次,基于GB/T 37778—2019和接头疲劳试验数据及不同焊缝长度模型的分析结果,总结适用于复杂结构激光焊连接静强度与疲劳强度的评估方法;再次,建立某弧焊-点焊-激光焊的不锈钢车体结构强度分析模型;最后,在EN 12663-1:2010+A1:2014规定的静态与动态载荷工况作用下,分析不锈钢车体侧墙激光焊连接强度。结果表明:AW3状态车钩压缩工况的车体侧墙中部上边梁区域的激光焊梁单元的最小安全系数为1.03;车体侧墙激光焊区域的梁单元的计算剪应力变化范围均远低于106次和107次的疲劳强度值,侧墙激光焊连接疲劳强度冗余大。

Finite element analysis method is used to study the simulation method and strength analysis of the laser welding connection of the stainless steel car body side wall.Firstly,the analysis models of solid,shell and beam elements to simulate the strength of semi-penetration lap laser welding,and the analysis models of beam elements to simulate different weld lengths were established respectively,and the weld element type suitable for the analysis of the strength of the laser welded connection of the complex structure is determined through the comparative analysis under the same calculation conditions.Next,joint fatigue test data and the analysis results of different weld length models,the evaluation methods for static strength and fatigue strength of laser welded connections for complex structures are summarized based on the GB/T 37778—2019 standard.Then,an analysis model for the structural strength of a stainless steel body by arc welding-spot welding-laser welding was established,and the laser welding connection strength of the stainless steel car body side wall is analyzed under the static and dynamic load conditions specified in the EN 12663-1:2010+A1:2014 standard.The results show that the minimum safety factor of the laser-welded beam element in the upper side beam area in the middle of the vehicle body side wall under the coupler compression condition of AW3 state is 1.03.The variation range of the calculated shear stress of the beam elements in the laser welding area of the car body side wall is far lower than the fatigue strength values of the 106th and 107th times,and the fatigue strength of the side wall laser welded connection is redundant.