Fatigue limit of blunt-notched components

MIRCO DANIEL CHAPETTI; KITANO, T; TAGAWA, T; MIYATA, T

FATIGUE & FRACTURE OF ENGINEERING MATERIALS & STRUCTURES (PRINT)

Blackwell Science Ltd.

Año: 1998 vol. 21 p. 1525 - 1536

8756-758X

The position and the effective resistance of microstructural barriers and their relation to the fatigue strength of blunt notched specimens are analyzed and modelled for three low carbon steel microstructures. A relationship for the notch size effect on the basis of the experimental evidence that the fatigue limit (both plain and notched) represents the threshold stress for the propagation of the nucleated microstructurally short cracks, was derived. The derived relationship characterizes the fatigue notch sensitivity by means of the parameter ktd defined as the stress concentration introduced by the notch at a distance d from the notch root surface equal to the distance between microstructural barriers, and was experimentally verified for two notch geometries in three microstructures: ferrite, ferrite-bainite and bainite-martensite