Comparison of Different Load Spectra on Residual Fatigue Lifetime of Railway Axle

Abstract

The railway axles are subjected to variable amplitude loading. The variability is caused by many different regimes of train operation. The dominant load is caused by the weight of the vehicle, which generates rotary bending during train movement. Nevertheless, there are additional forces, which are generated when train goes through curved track, over crossovers, switches, rail joints etc. Present non-destructive defectoscopy can reliably detect only relatively long cracks (approximately 2 mm long or longer). Hence there is a risk that the existing crack is not detected. Therefore, for conservative estimation of the residual fatigue lifetime the railway axle with a crack should be considered. The behaviour of the crack depends on load spectrum of railway axle. Hence for accurate determination of residual fatigue lifetime of the railway axle is necessary to know representative load spectrum. This paper compares several measured load spectra of railway axles, which are available in the literature. The effect of different load spectra is shown on two widely used materials for railway axles: EA1N and EA4T steels. Obtained results could be used for safer operation of railway axles.The railway axles are subjected to variable amplitude loading. The variability is caused by many different regimes of train operation. The dominant load is caused by the weight of the vehicle, which generates rotary bending during train movement. Nevertheless, there are additional forces, which are generated when train goes through curved track, over crossovers, switches, rail joints etc. Present non-destructive defectoscopy can reliably detect only relatively long cracks (approximately 2 mm long or longer). Hence there is a risk that the existing crack is not detected. Therefore, for conservative estimation of the residual fatigue lifetime the railway axle with a crack should be considered. The behaviour of the crack depends on load spectrum of railway axle. Hence for accurate determination of residual fatigue lifetime of the railway axle is necessary to know representative load spectrum. This paper compares several measured load spectra of railway axles, which are available in the literature. The effect of different load spectra is shown on two widely used materials for railway axles: EA1N and EA4T steels. Obtained results could be used for safer operation of railway axles.