Estimation of Elastic-Plastic Behavior at Notches under Uniaxial Cyclic Loading

An accurate prediction of elasto-plastic cyclic deformation becomes extremely important in design optimization. It also leads to more accurate fatigue life prediction and hence weight savings. In paper presents a two-stage notch root prediction method. This is based on a correction expression to Neuber's rule notch strain amplitude as the first stage, and a linear interpolation scheme as the second stage. The accuracy of this method is assessed by comparing the predicted results with the results obtained from elasto-plastic finite element analysis. Various types of steels with different yield strengths were used in this study. Notch deformation behavior under cyclic variable amplitude loading conditions was monitored for a double notched flat plate and a circumference notched round bar to cover plain stress and plain strain conditions. Elastic as well as elasto-plastic finite element analyses are performed. Notch strain amplitudes in addition to fatigue life predictions obtained using the proposed method are in a good agreement with the elasto-plastic finite element analysis when compared to predictions obtained using Neuber's rule.