Abstract: 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.

Key words: Deformation, Heat source model, Stress field, Temperature field