A simplified fatigue assessment method for transverse fillet welded joints

Under the as-welded condition the fatigue crack initiation period was considered non-existent and Linear Elastic Fracture Mechanics (LEFM) was used to calculate fatigue strength for a range of weld geometries. Fracture mechanics assessment of welded joints requires accurate solutions for stress intensity factor (SIF). However, the solutions for the SIF of complex welded joints are difficult to determine due to the complicated correction factors. Three methods for SIF prediction are discussed on fillet welded specimens containing continuous or semi-elliptical surface cracks, including the traditional correction method Mk, the approximate correction method Kt, and the suggested additional crack size method (ac+ae). The new additional crack parameter ae is used to replace the stress concentration effect of weld profile Mk, which simplifies the calculation process. Experimental results are collected to support fatigue strength assessment of the additional crack size method.