Integrated Modelling of Crack Propagation in AA2024-T3 FSW Butt Joints Considering The Residual Stresses from the Manufacturing Process

This paper deals with numerical and experimental investigation on the influence of residual stresses on fatigue crack growth in AA2024-T3 friction stir welded butt joints. An integrated FEM-DBEM procedure for the simulation of crack propagation is proposed and discussed. A numerical FEM model of the welding process of precipitation hardenable AA2024-T3 aluminum alloy is employed in order to predict the induced residual stress field. The reliability of the FEM simulations with respect to the induced residual stresses is assessed comparing numerical outcomes with experimental data obtained by means of the contour method. The computed stress field is transferred to a DBEM environment and superimposed to the stress field produced by a remote fatigue traction load applied on the friction stir welded cracked specimen. Numerical results are compared with experiments showing good agreement and highlighting the predictive capability of the proposed method. Furthermore, the influence of the residual stress distribution on crack growth is evidenced.