Fatigue assessment of old design axles: Service simulation and life extension

This paper proposes a damage-tolerant approach for ensuring the safe operation of railway axles with an old, non-EN-compliant design, until completion of their life cycle. The approach consists in defining a suitable non-destructive testing (NDT) inspection programme, which is based on the precise evaluation of service loads using multi-body simulation and on validated crack propagation models. The application of the proposed approach is presented for two different test cases, both representing old design axles for urban railway vehicles. It is demonstrated that NDT inspection intervals are highly dependent on the specific axle design and service scenarios, particularly with regard to the effects of braking.