Numerical simulation of friction stir butt welding process for AA5083-H18 sheets

Thermo-mechanical simulation of the friction stir butt welding (FSBW) process was performed for AA5083-H18 sheets, utilizing a commercial finite volume method (FVM) code, STAR-CCM+, which is based on the Eulerian formulation. Distributions of temperature and strain rate histories were calculated under the steady state condition and simulated temperature distributions (profiles and peak values) were compared with experiments. It was found that including proper thermal boundary condition for the backing plate (anvil) is critical for accurate simulation results. Based on the simulation, thermal and deformation histories of material elements were also calculated, useful to predict material characteristics of the weld such as hardness or grain size, and possibly for the susceptibility of weld to abnormal grain growth (AGG) after post-weld heat treatment.