Fatigue limit prediction of notched hard steel parts under uniaxial and torsional loading

摘要

The fatigue limit of notched and smooth specimens of a bainitic bearing steel is measured and calculated under tension-compression,repeated tension,rotating bending and alter-nating torsion.The notch effect in this steel can be fully explained as a statistical size and multiaxiality effect.The calculation is based on the weakest link model after Weibull and a new three-parametric high cycle fatigue criterio,which includes the effect of multiaxiality and mean stresses.It is shown that the physical basis of the weakest-link model are inclusions which cause crack initiation at the fatigue limit,if the stressed volume exceeds a certain value.