An integrated approach to rolling contact sub-surface fatigue assessment of railway wheels

A rolling contact fatigue assessment procedure for railway wheels is presented. The method aims to define the time required for the nucleation of sub-surface cracks in the wheel rim under different service conditions. The approach combines fatigue damage evaluation with dynamic loads simulation, by the application of multiaxial fatigue criteria to the contact stress histories. Material fatigue properties were obtained from both uniaxial tension-compression and reversed torsion stress conditions on specimens directly extracted from wheels. To validate the multiaxial model, non-proportional combined torsion and pulsating tests were also performed.