Fatigue Strength Assessment of the Cruciform Fillet Welded Joints Using Hot-spot Stress Approach

In this study, fatigue tests to obtain S-N curves and FE analyses to obtain structural stress concentration factors were conducted for the two types of cruciform fillet welded joints, that is, load-carrying and non load-carrying types. Then me changed the obtained S-N curve of load-carrying joint to that based on hot-spot stress. As a result, the S-N curve of load-canying joint based on hot-spot stress was almost exactly coincided with that of non load-carrying joint based on nominal stress. So we have concluded that the fatigue strength of a welded joint with different geometry from the non load-carrying cruciform joint could be estimated by the structural stress concentration factor obtained by considering the stress distributions along the expected crack path.