Fatigue Analysis of Nuclear Welded Structures Based on Structural Stress and Elasto-Plastic Fracture Mechanics Approach

In the paper, the validity of the modified mesh-insensitive SS (structural stress) procedure to apply to the welded joints with local thickness variation is identified via the comparison of SCFs (stress concentration factors) calculated for various FE (finite element) models. FCI (fatigue crac kinitiation) cycles are determined by using the SS/EPFM (elasto-plastic fracture mechanics) approach and the various fatigue crack growth models. Fatigue test is performed to identify the validity of the fatigue analysis results. Finally, as a result of comparison among test and various analysis results, it is found that the SS/FM (fracture mechanics) approach agrees well with the fatigue test results over all cycle regions and the SS/EPFM approach is more reliable than the SS/LEFM (linear elastic fracture mechanics) approach.