RESEARCH OF THE FATIGUE CRACK PROPAGATION CHARACTERISTIC ON RAILWAY HOLLOW AXLES

The service loads of the axles were defined. According to the load spectrum from the measured dynamic stress of the hollow axles, the stress distribution on the high-speed axle profile is obtained by Finite Element calculating. Although the axle belongs to giga-cycles fatigue component, here, a foreign object damage and other causes may resulting in surface cracks on the axle are considered. At the same time, the initial surface cracks size is given according to the non-damage test technology. Based on the linear elastic fracture mechanics theory，the relation between the stress intensity factor and the crack size was also studied. According to the fatigue crack propagation equation and the corresponding crack propagation threshold，the propagation rate and fatigue life of a given crack with initial size were calculated. Then the paper gave the running distances before the crack propagates to the critical length, and the reference values for the examining and repairing limit of the hollow axle.