抄録
In previous studies, authors proposed the evaluation method of fatigue strength of cast or forged materials which have a small flaw or a macro round-shaped flaw by fracture mechanics analysis using 'intrinsic crack medel'. In this study, we discussed the estimation method of fatigue notch sensitivity factors, which are commonly used in the fatigue design of notched members, by fracture mechanics analysis using 'intrinsic crack model'. We also discussed fatigue limits of notches by fracture mechanics analysis using 'intrinsic crack model' and the local stress distribution in the notch root. The results obtained are as follows, (1) Fatigue notch sensitivity factors can be well derived by fracture mechanics analysis using 'intrinsic crack model'. This method well describes the experimental results conducted in this study and the data by other researchers. (2) Fracture mechanics analysis using 'intrinsic crack model' has the possibility to describe the ρ-η curves, which are commonly used in the simply estimation of fatigue notch sensitivity factors. (3) Fatigue limit of notches can also be well estimated by fracture mechanics analysis using 'intrinsic crack model' and the local stress distribution in the notch root. (4) The fatigue limit estimation method proposed in this study has the possibility to estimate fatigue limits of the notches of which local stresses are obtained by FEM.
