Fatigue assessment of axles with old design: a damage tolerance approach as support to ‘life extension’

This paper presents an approach for extending the service life of ‘old’ railway axles, that were designed in the past based on criteria not compliant to the axle design directives presently in force in Europe. To this aim, a fault-tolerant approach is defined, combining the use of multi-body simulation for the definition of the axle service loads, of Finite Element calculations and of crack propagation models, with the final aim of defining a suitable program of non-destructive inspection intervals allowing to service the wheelsets until the end of their service life. The proposed approach is applied on two test cases, both representing old design axles for urban railway vehicles.