Crack Propagation and Rail Surface Spalling Mechanism Based on Peridynamics

Abstract:

Rail surface rolling contact fatigue （RCF） crack propagation model based on state peridynamics was established to research the propagation of RCF crack and the formation process of spalling. It was found that the crack propagation path gradually turned towards into the internal rail with the accumulation of traffic tonnage in the case of single crack or cracks with distance longer than 1.5 mm between each other. The propagation rate gradually decreases with the increase of traffic tonnage and crack length. In the case of multiple cracks， the cracks propagated along their length direction below traffic tonnage of about 8.8 Mt. After the traffic exceeded 8.8 Mt， the secondary damage between cracks was formed especially between the cracks which their distance was less than 1.5 mm. If the distance between cracks was longer than 1.5 mm， the interaction among cracks was reduced. In the case of multiple cracks with adjacent distance less than 1.5 mm， the spalling occurred from the secondary damage when the increment of traffic tonnage reached a certain amount （>10.0 Mt）. At that time， the spalling depth was about over 1/2 depth of the crack.

Key words:railway;rail;spalling;crack propagation;peridynamics