Fracture Mechanics Analysis and Evaluation of the Fatigue Strength of Spot Welded Joints

The stress intensity factors for various spot welded joints such as tensile-shear, cross- tension, T type tension and bending specimens, are analysed by finite element method. The fatigue strength and the fatigue crack pathes for these specimens can be well characterized by the stress intesity factors analysed and a mixed mode fracture criterion. It is found that fracture mechanics is a powerfull approach to evaluate the fatigue strength for various spot welded joint specimens with different loading systems, plate thicknesses and nugget diameters.