Determining fatigue life of bent and tensioned elements with a notch, with use of fictitious radius

Abstract

The work presents verification of Neuber's fictitious radius method, used in fatigue life calculation of notched elements and welded joints. Stress values, calculated according with fictitious radius method, were compared with smooth specimens Basquin fatigue curves, and number of cycles was read. However, obtained calculated number of cycles of fatigue life does not correspond to experimental fatigue life, especially in a low cycle fatigue range. Hence, different equivalent microstructural length values were calculated for different loading levels. It was observed that equivalent microstructural length depends on loading level and type of loading. Finally, equivalent microstructural length was presented in a linear regression equation, as dependant on loading level and its relation to yield strength.