A6061铝合金脉冲MIG焊T型接头应力场有限元模拟

Finite Element Simulation of Stress Field of A6061 Aluminum Alloy Pulse MIG T-Joint

基于B样条拟合非线性曲面的优势建立B样条焊缝模型,根据脉冲熔化极惰性气体保护(MIG)焊接基-峰值电流热输入特点建立高斯面+锥形体组合热源模型,采用该模型模拟A6061铝合金脉冲MIG焊T型接头的温度场及应力场,并进行了试验验证。结果表明:模拟所得T型接头熔池的熔深和熔宽以及特征点峰值温度与试验结果间的相对误差不大于1.4%,验证了模型的准确性。在距焊缝中心约10 mm和30 mm处的纵向残余应力模拟结果与试验结果间的相对误差分别为28.0%和20.6%,其计算精度比采用简化焊缝及双椭球热源模型至少提高了15.7%。

B-spline weld model was established based on the advantages of B-spline fitting nonlinear surface,and the combined heat source model of Gaussian surface and conical body was established based on characteristics of pulse MIG welding base-peak current heat input.The temperature field and stress field of pulsed metal inert-gas(MIG) welded T-joint of A6061 aluminum alloy were simulated by the models,and were verified by the tests.The results show that the relative errors between the molten pool depth and width and the characteristic point peak temperatrue of T-joint by simulation and test results were less than 1.4%,proving the accuracy of the model.The relative errors of the longitudinal residual stress at about 10 mm and 30 mm away from the weld center between the simulation and the test results were 28.0% and 20.6%,respectively,and the calculation accuracy was at least 15.7% higher than that by the simplified weld and double ellipsoid heat source model.