Fatigue Life Evaluation by ${\sigma}-N$ and ${\epsilon}-N$ Approaches Considering Residual Stresses

잔류응력을 고려한 국부변형률과 공칭응력 기준 피로수명 평가

To evaluate the fatigue lives of welded joints taking into residual stress relaxation, two approaches are applied. One is based on the conventional local strain analyses. The other is based on a model developed by the authors. In the first approach, the Ramberg-Osgood relation, Lawrence model and S.W.T. parameter are used. In the second approach, The S-N curve for a welded joint is deduced from that of the parent material. Residual stress relaxation obtained by finite element analysis is considered. Finally, we evaluate the fatigue lives for four weld details using the two approaches.