Analysis and modelling of fatigue failure of friction stir welded aluminum alloy single-lap joints

The fatigue strength of 2024-T3 aluminum alloy friction stir welded single-lap joints is determined by the presence of two crack-like unwelded zones at the overlap ends. Besides, mixed mode I/II conditions are present at the crack tip as the joint is prevalently loaded in shear. In this work, a finite element analysis is performed to predict the crack path and the stress intensity factor at the crack tip, then the lifetime is estimated by examining the crack propagation behaviour of the base material using the AFgrow software. The effect of an initial overload is also considered. The crack path is investigated optically and using the “fatigue failure mechanism map”.