FE-based Fatigue Life Prediction Techniques for Welded Automotive Structures

This paper presents new FE-based fatigue life prediction techniques for spot-welded and arc-welded structures. The nominal structural stress is the fatigue parameter for spot-welded joints and derived from forces and moments acting on spot weld nuggets. The use of forces and moments at shell elements improves the prediction of stress around a nugget. The technique for arc welds is the structural stress approach that considers the proportion of membrane stress component to bending stress component. Proposed techniques for both spot-welded and arc-welded structures are adequate for the fatigue life predictions even when using coarse FE meshes.