Prediction of the fatigue life of a notched body by the local stress-strain state. Part 1. Determination of stresses and strains in a notch under elastoplastic cyclic deformation

Abstract

We have carried out an experimental investigation of local strains in specimens with various stress concentrators under cyclic and monotonic loading conditions. The strains in notches were measured by a strain gauge with a small nominal length. Using the test results for, smooth specimens, we have plotted cyclic stress-strain diagrams for steel and two aluminum alloys. The values of the full strain amplitude calculated by the known approximate methods were compared with experimental data. The Neuber formula with the Makhutov correction function has been found to ensure the best agreement with the experimental data. We have given recommendations regarding the application of this function for calculating the local strain amplitudes under loads corresponding to high-cycle fatigue and to a region of transition from low- to high-cycle fatigue.