Effect of creepages on stress intensity factors of rolling contact fatigue cracks

In heavy-haul railway systems, the experience of high traction force of rails in curved tracks significantly accelerates the rolling contact fatigue crack growth. The overall level of traction force and its detailed distribution within a contact patch can be determined by the extent of wheel slips in different directions, also referred to as creepage. However, few studies have focused on quantifying the influence of creepage on rolling contact fatigue crack growth behaviour. In this paper, a numerical method is proposed to investigate the non-proportional mixed-mode rolling contact fatigue crack growth behaviour in the presence of severe longitudinal, lateral and spin creepages. To partially validate the proposed numerical method, the predicted crack growth directions on the rail surface are compared with the cracking patterns obtained from field observations. A parametric study is also conducted to further quantify the influence of different creepage combinations on the evolution of stress intensity factors at the crack front. Results show that both lateral and spin creepages can significantly affect the phase and maximum magnitude of KII and KIII during one complete loading cycle. Moreover, the increase of spin creepage is found to have a more detrimental effect on overall RCF crack driving force than the increase of the other two creepage components.

Automated summary

In heavy-haul railway systems, the high traction force in curved tracks accelerates rolling contact fatigue crack growth. However, there is limited research on the influence of creepage on this crack growth behavior. This paper proposes a numerical method to investigate non-proportional mixed-mode crack growth in the presence of severe creepage. Results show that lateral and spin creepages significantly affect the phase and magnitude of stress intensity factors, with spin creepage having a more detrimental effect.