Numerical Crack Growth Analysis in AA2024-T3 Friction Stir Welded Butt Joints

This paper deals with a numerical investigation on the influence of residual stresses on fatigue crack growth in AA2024-T3 friction stir welded butt joints. The computational approach is based on the coupled usage of the finite element method (FEM) and the dual boundary element method (DBEM), in order to take advantage of the main capabilities of the two methods. Linear elastic FE simulations are performed to evaluate the process induced residual stresses, by means of the “contour method” technique. The computed stress field is then superimposed on the stress field produced by a remote fatigue traction load applied on a cracked specimen, and the crack propagation is simulated in a DBEM environment, according to a two-parameters growth model. The results obtained highlight the influence of the residual stress distribution on crack growth.