A Comparative Study of the Fatigue Behavior of Spot Welded and Mechanically Fastened Aluminum Joints

The cyclic behavior of single overlap aluminum joints joined through a number of different methods has been investigated using Alcan 5754-O, an alloy that potentially could be used in structural applications. Overlap shear tests of spot welded, clinched and riveted joints are compared on the basis of their fatigue performance. The fatigue response of the spot welded joint was the baseline to which the other fasteners were compared. Test results showed an improvement of approximately 25% for both the mechanical clinch joints and aluminum rivets in fatigue strength at 10⁶ cycles. The most significant improvement in fatigue strength of 100% was found for the self piercing rivets at 10⁶ cycles. The failure behavior of the various joining methods is discussed as well as the surface appearance.