抄録
A hypothesis of fatigue plastic adaptation is proposed and modeled as one idea that is available to combine microscopic and macroscopic approaches to fatigue plasticity. The hypothesis expresses that, in a surface layer, at a notch root and at a fatigue crack tip, elastic deformation for the maximum stress is transformed into localized inhomogeneous plastic deformation inherent in fatigue. Based on the hypothesis, an equivalent stress ratio is formulated as a parameter for correspondence between cyclic stress conditions of notched and unnotched specimens and is applied to some published experimental data including different cyclic loading types of torsion, bending and their combination.
