6061-T6铝合金中厚板-节点套多层多道焊数值模拟

为研究铝合金中厚板-节点套接头在多层多道焊后的残余应力和变形分布,本文基于ABAQUS软件建立了该接头三维有限元模型,采用双椭球热源、生死单元法以及顺序耦合法,对6061-T6铝合金中厚板-节点套多层多道焊进行数值模拟,并分析了接头的温度场,以及在夹具约束下的焊接残余应力及变形的分布情况。研究结果表明:数值模拟与实际接头的熔池形状吻合度较高；摆动焊接过程中温度曲线呈多峰结构；焊件的升温速率明显大于冷却速率,且冷却速率随时间逐渐减小；焊接残余应力主要集中在焊缝及夹具区域,且小于6061-T6铝合金在室温下的屈服强度；接头的最大横向残余应力为129.9 MPa,中厚板上的横向残余应力大于节点套上的横向残余应力；接头的最大纵向残余应力为132.9 MPa,沿焊接方向,焊缝处的纵向残余应力呈山峰状分布；该接头在Y轴方向上的变形最大,为1.494 mm,该接头的最终变形结果为上凸变形。

Numerical simulation of multi-pass welding between 6061-T6 aluminum alloy medium thick plate and sleeve

To study the distribution of the residual stress and deformation of aluminum alloy plate-to-sleeve joints after multi-pass welding, a three-dimensional finite element model of the joint established based on ABAQUS software. The double ellipsoid heat source, element birth and death method and sequential coupling method were all applied to simulate the multi-pass welding of 6061-T6 aluminum alloy plate-to-sleeve joint. The temperature field of the joint and the distribution of welding residual stress and deformation under clamping constraints was analyzed. The results show that the simulated molten pool morphology accords with the experimental one. The temperature curve shows a multi-peak structure during the weaving welding process. The heating rate of the weldment is greater than the cooling rate, and the cooling rate decreases with time. The welding residual stress is mainly concentrated in the weld and clamping area and it is less than the yield strength of 6061-T6 aluminum alloy at room temperature. The maximum transverse residual stress of the joint is 129.9 MPa, and the transverse residual stress on the medium-thick plate is greater than that on the sleeve. The maximum longitudinal residual stress of the joint is 132.9 MPa. Along the welding direction, the longitudinal residual stress distribution at the weld is as a mountain shape. The maximum deformation of the joint is 1.494 mm in the Y-axis direction, and the final deformation of the joint is convex.