复杂航天筒体结构件的焊接应力应变演变规律

采用有限元分析手段对复杂航天筒体结构件的纵向和环向焊缝温度场和应力场进行模拟。航天筒体焊接采用变极性等离子弧焊工艺，根据变极性等离子弧焊工艺特点使用面高斯热源和圆柱热源的组合热源模型作为变极性等离子弧焊的热源。采用ANSYS软件中ANSYS参数化设计语言(ANSYS parametric design language, APDL)编写程序，实现变极性等离子弧焊接热源在筒体结构上加载和移动，完成四道纵缝和两道环缝的焊接热力过程仿真。通过对模拟结果分析，解释复杂筒体焊接应力应变的演变过程。发现在焊接过程中纵缝两端有明显的应力-应变释放，交叉部位的变形直接影响到结构整体的尺寸精度。

Stress and Strain Evolution Rule Research on Aerospace Aluminum Alloy Cylinder Structure Welding

The stress and strain in Aluminum cylinder longitudinal and circumferential weld seam are simulated by finite element analysis tools-ANSYS. Tube structure in aerospace is welded by the variable polarity plasma arc welding process. According to the characteristics of variable polarity plasma arc weld, surface heat source and cylindrical heat source are used to simulate variable polarity plasma arc weld. The program which is used to achieve loading and moving variable polarity plasma arc(VPPA) welding heat is wrote by using the ANSYS parametric design language(APDL) in ANSYS software. The same structure in different type of weld is presented by the different ways of loading heat source. The use of sweep meshing method to build complex cylinder structure analysis model is proposed. Through the simulation results, the complex cylinder welding deformation evolution process is explained. It is found that longitudinal seam ends have obvious stress-strain release in the process, and cross section deformation directly influenced the size precision of whole structure.