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 summarized. 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 different 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.

A series of probabilistic analyses have been carried out for obtaining a minimum safety factor ηD to be adopted for design of railway axles (prospective life 106 km). The safety factor is controlled the dispersion of fatigue strength and uncertainty of the stress spectrum.Figure optionsDownload as PowerPoint slide