Numerical determination of residual stress in friction stir weld using 3D-analytical model of stir zone

Heat generation due to plastic work is the dominating term during the steady state friction stir welding (FSW) process. Based on this phenomenon a 3D-analytical model of the stir zone around the FSW tool pin has been developed. In this model, the friction force during steady state FSW process has been neglected as the material in this zone is plasticized and it has undergone plastic deformation rather than inducing friction to the tool pin boundary. The 3D-analytical model has been used for FE analysis to predict heat distribution and based on this thermal history the residual stress distribution in the stir zone, heat affected zone and the base metal (Al6061-T6) were predicted and found reasonable agreement with the experimentally measured values.