考虑铝合金接头软化的焊接变形及残余应力预测方法

High precision prediction method of residual stress and welding distortion of aluminum alloy sheet

针对铝合金焊接接头的软化问题,通过采用合理材料模型对该问题进行了描述,并在此基础上开发了相应的热-弹-塑性有限元计算方法来预测铝合金薄板的焊接变形和残余应力.以TIG重熔铝合金薄板为例,模拟分析了焊接过程中的温度场、残余应力和焊接变形.同时,采用试验方法测量了焊件的挠曲变形.结果表明,考虑软化现象的有限元数值计算结果与试验测量结果更吻合,验证了提出材料模型和所开发的有限元计算方法的有效性;对于接头软化较为明显的铝合金材料,进行焊接残余应力的数值模拟时有必要建立反映接头软化的材料模型.

In this paper,a new material model with considering softening phenomena in aluminum alloy welded joint was developed to accurately calculate welding residual stress and deformation. In the current study,the welding residual stress and distortion in a 6061 aluminum alloy bead-on joint performed by TIG welding process was simulated by using the developed computational approach. Meanwhile,the out-of-plane deformations were measured by experiment,and the measurements were used to verify the numerical results. The numerical results show that softening effect has a significant influence on longitudinal residual stress,which has a limited influence on transverse residual stress. It seems that the softening effect could only influence on welding deformation.