沟槽蒙皮结构激光焊接应力和变形的数值模拟

Numerical simulation of residual stress and deformation on laser welding of "grooved-coat" structure

关键词:  激光焊  数值模拟  残余应力  焊接变形

Key words:  laser welding  numerical simulation  residual stress  welding distortion

摘要:

利用有限元分析软件MARC对"沟槽-蒙皮"结构的激光焊接过程进行三维数值模拟,涉及了激光焊接复合热源模型的确定,热力学边界条件的简化,数值模拟温度场的验证,以及残余变形和应力分布结果的分析和讨论。研究了结构上规则排列的多道焊缝的施焊顺序对焊接残余应力和变形的影响。结果表明,不同焊接顺序所产生的变形状态相同,变形量有区别,而残余应力的分布则不同,以由外向中的对称顺序进行焊接时,结构的焊后残余变形最小,残余应力的分布比较均匀,峰值最小。

Abstract:

Based on finite element analysis software MARC, the 3D numerical simulation on laser welding of "grooved-coat" structure was conducted.This research work concerned the application of hybrid heat source model of laser welding, the simplifications of the mechanical and thermal boundary conditions, the discussions on the computed results of temperature field and residual stress field, and that of the comparison between the shape and size of computed weld pool and the experimental results.The results of the comparisons show that the finite element model is reasonable.The effects of the welding sequences on the welding residual stresses and deformation of structure were investigated.The results show that different welding sequence can get the same distortion pattern, but their deformation have difference, and the distribution of the residual stress is different from each other.The deformation and the residual stress obtained with symmetrical welding from outer to inner is the lowest.