Fatigue limit and residual life evaluation of railway EA4T axles with artificial surface impacts

The present paper aimed at investigating the effect of foreign object damage (FOD) on the high-cycle fatigue resistance and remaining life of high-speed railway axle. The commercial compressed gas was used to prefabricate the impact surface damage on the specimen taken from the actual axle surface. The probabilistic fatigue curves and fatigue limits of smoothed and FODed specimens were obtained according to the Owen tolerance limit method. Due to the variations of loads, surface qualities and sizes between the small-sized specimens and full-scale axles, the fatigue limits of damaged specimens were modified for assessing the service performance of full-scale axles. In addition, theoretical fatigue limits evaluated by the Peterson formula under two impact velocities (100 and 138 m/s) were more conservative than the experimental values by the effects of residual stress and microdamage. Finally, the service life of impact-damaged axles was calculated by the modified Miner theoretical formula to determine a reasonable inspection period for axles.