구조응력 및 파괴역학 방법에 근거한 원전 용접구조물의 피로균열 개시 수명 평가

The mesh-insensitive structural stress procedure by Dong is modified to apply to the welded joints with local thickness variation and in ignorable shear/normal stresses along local discontinuity surface. Validity of the modified mesh-insensitive structural stress procedure is identified comparing the structural stresses calculated for various FE models. Fatigue crack initiation cycles are determined by using the structural stresses 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 between test and analysis results, it is found that the structural stress/fracture mechanics approach is valid for fatigue analysis and the requirements for development of a new fatigue crack initiation analysis procedure are presented.