基于热弹塑性理论性，建立铝合金激光+熔化极惰性气体保护焊（Metal inert gas，MIG）复合热源焊残余应力的三维数值分析模型。激光和电弧热输入分别采用双椭球体热源模型和热流密度峰值指数递增的锥体热源模型描述。利用所建模型，通过ANSYS有限元软件对12 mm厚铝合金复合焊对接接头残余应力进行模拟计算，研究其分布特征，并与MIG焊的计算结果进行比较。同时，将温度场与残余应力的计算结果与试验结果进行对比，验证模型的准确性。研究结果表明，在焊缝及近缝区，纵向拉应力及等效残余应力较大，两者应力峰值均低于材料的屈服强度。而相较于电弧作用区域，激光作用区域残余应力相对较高。焊趾处横向残余表现为拉应力，但应力峰值相对较低。与MIG多层多道焊相比，复合焊纵向应力和等效应力高应力区域明显较窄；焊件上表面复合焊应力峰值小于MIG焊，但下表面应力峰值则较MIG焊大。
胥国祥
,
郭庆虎
,
胡庆贤
,
朱杰
,
刘朋
,
潘海潮
. 中厚板铝合金光纤激光+MIG复合热源焊残余应力的数值分析[J]. 机械工程学报, 2018
, 54(2)
: 77
-83
.
DOI: 10.3901/JME.2018.02.077
Based on thermal-elastic-plastic theory, a three dimensional numerical model of residual stress in laser+metal inert gas (MIG) hybrid welding of aluminum alloy is developed. The laser and arc heat inputs are modeled as the double ellipsoid heat source and the cone heat source with exponentially enhanced power density along the central axis, respectively. Using the built model, the residual stress in hybrid butt welding of 12 mm thick aluminum alloy is calculated through ANSYS finite element software and its distribution feature is analyzed, which is also compared with that of MIG welding. The calculated results of temperature and residual stress fields are compared with the experimental data to validate the accuracy of the model. Results show that, in and near weld zone, both the longitudinal tensile stress and Von-Mises equivalent stress are higher, their peak values being lower than the yielding stress of base metal. In addition, the stress in laser action zone is larger than that in arc action domain. A transversal tensile stress is generated at weld toe but its peak value is small. Compared with those of multi-pass and multi-layer MIG welding, the high stress is narrower. The peak stress at top surface of workpiece in hybrid welding is lower than that in MIG welding. But, at the workpiece bottom surface, the former is greater than the latter.
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