Numerical analysis of stress concentration factors in notched specimens according to ISO 3928

An FEM analysis was performed to determine the stress concentration factors in fatigue testing specimens according to the principal geometry defined in ISO 3928. The notch radius and the specimen height were systematically varied. Aside from axial loading, two bending modes were distinguished and, for the first time, the stress concentration factors were calculated for torsion testing. In this context, the highly stressed volume was determined for unnotched bars, including a new geometry suitable for tensile and fatigue testing. Applying a simplified form of Weibull_s equation, it was possible to normalize fatigue strengths from different testing conditions to a common relationship between strength and density.