关键词: 残余变形, 残余应力, 搅拌摩擦焊, 数值模拟

Abstract: The technology of numerical simulation is increasingly applied to the study of friction stir welding (FSW), so the research must be carried out to improve the accuracy of simulation model. Based on some available information about thermal-mechanical coupled analysis in FSW and actual experiments, a more precise numerical simulation model of FSW is set up. Several issues of FSW process are carefully discussed, including heat generation, material model, the restriction of welding fixtures and the functions of stir tool’s mechanical load. In the new model, the heat generation is considered to be driven by yield shear stress of base material, and the mechanical properties of material are temperature or temperature history dependent, and the contact relation between welding fixtures and structure is established, and the stir tool’s mechanical loads are introduced into the mechanical analysis model in a simplified way. By means of the newly-established model, a numerical simulation of FSW is carried out on aluminum alloy sheet, which generates the results similar to those from actual experiments on temperature field, residual stress and deformation.

Key words: Friction stir welding, Numerical simulation, Residual deformation, Residual stress