PROBABILISTIC MODEL ON STATISTICAL FATIGUE PROPERTY IN VERY HIGH CYCLE REGIME BASED ON DISTRIBUTIONS OF SIZE AND LOCATION OF INTERIOR INCLUSIONS

摘要

In S-N diagrams for high strength steels, the duplex S-N curves for surface-initiated fracture and interior inclusion-initiated fracture were usually confirmed in the very high cycle regime. This trend is more distinct in the loading type of rotating bending due to the stress distribution. In the case of interior fracture mode, the fish-eye is usually observed on the fracture surface and an inclusion is also observed at the center of the fish-eye. In the present work, the authors have attempted to construct a probabilistic model on the statistical fatigue property in the interior fracture mode based on the distribution characteristics of the location and the size of the interior inclusion at the crack initiation site.