Fatigue Life Predictions of Friction Stir Welded Joints by Using Fracture Mechanics Methods

The deterioration of the airframe due to fatigue loading and corrosion attack should be monitored by scheduled periodic inspections to assure the appropriate detection of the damaged area. In the present investigation an exploratory test program has been carried out to improve the general understanding of the fatigue behaviour of undamaged and corrosion damaged joints. Also the sequence effects in FSW joints are studied. The aim is to offer a basis both for a better experimental documentation as well as for an evaluation of existing crack propagation prediction models. Moreover specifically existent fracture mechanics principles are applied to friction stir welded structures. The objective is to elaborate an easy, practical and reliable engineering approach to perform life predictions of friction stir welded structures under in-service loading and in the presence of corrosion attack.