Fatigue strength assessment of railway axles considering small-scale tests and damage calculations

Small scale fatigue tests aimed at determining the S-N diagram and the Miner Index to be adopted for fatigue damage assessment of railway axles were carried out within the frame of the frame of the research activities of EU funded EURAXLES project. Fatigue tests performed on steel grades EA4T and EA1N adopted by the European EN13103/13104 standards with both constant and variable amplitude loading are reported. The variable amplitude loading fatigue tests were carried out by using loading spectra derived from actual load measurements of fatigue bending moment in railway axles under significant service conditions. The consistent version of Miner's rule (according to the FKM-Guideline) with an allowable damage sum Dcrit = 0.3 adopted in combination with 2.5% percentile (p2.5%) of the S-N curve derived experimentally with small specimens proved to be adequate as design criterion, thus enabling the transferability of small scale fatigue tests to full scale railway axles that would lead to improved fatigue resistance of railway axles with new designs.