Probabilistic fatigue assessment for railway axles and derivation of a simple format for damage calculations

This paper describes a procedure for the determination of railway axle risk of fatigue failure under service loading for a simple fatigue assessment compliant to modern structural recommendations. After an initial review of reliability assessment under fatigue, a fully probabilistic approach is outlined, whose input data for the fatigue damage obtained with the EURAXLES project are briefly summarised. Then, a series of Montecarlo simulations was carried out in order to determine the maximum allowable stress for a given axle made of EA4T and EA1N under service conditions identified by di↵erent load spectra from the literature. Results have been obtained in terms of a safety factor for damage calculations that allows designers to adopt a simple semi-probabilistic approach for designing axles for a target reliability against fatigue. The application of this procedure to a railway axle then shows how safety factors should be have to be further increased for taking into the prospective presence of impact damages.