Numerical Fatigue Analysis of Dissimilar Lap Joints Fabricated by Dimple Spot Welding for Automotive Application

This paper presents a numerical analysis of dimple spot welding (DSW) as an innovative joining technique for dissimilar materials, namely steel and aluminium alloys. Employing a finite element (FE) model, the study simulates the fatigue performance of DSW joints, considering crucial factors such as contact friction and cyclic loading conditions. While various numerical models are proposed, the simulation incorporating friction and fatigue loading appears to offer the highest accuracy. The research highlights that the fatigue behaviour of DSW joints can be effectively investigated through the non-local theory of the implicit gradient approach by utilising the fatigue curve of arc-welded structures composed of steel or aluminium alloys. Specifically, simulations incorporating friction and fatigue loading demonstrate that the steel spot weld does not represent the weakest point within the joints.