Finite Element Modelling of Friction Stir Welding of Aluminium Alloy Plates-Inverse Analysis using a Genetic Algorithm

This paper presents finite element simulation results of instrumented FSW experiments on aluminium alloys 6005A-T6 and 2024-T3. The SAMCEF™ finite element code is used to perform the simulations. The FE model involves a sequential thermal-mechanical analysis and includes contact between the meshed tool, workpiece and backing plate. The model takes into account the pressure applied by the tool on the weld as well as the heat input. The heat transfers such as convection in air and contact conductance with the backing plate are modelled. For each experiment, the temperature time-histories were recorded at several locations in the workpiece. The heat input in the finite element model is identified by minimising the objective function of a constrained problem using a genetic optimisation algorithm. The objective function is the square of the difference between the experimental measurements and the numerical prediction of temperature. Finally, levels of residual stress predicted by simulation are presented.