Study On The Changing Regularity Of Residual Stress In The Process Of Rail Causative

Railway development is related to the national economy andpeople’s livelihood, and the modernization of railway high-speed, heavy-load andhigh-density transport organization need high quality of rail. The different stress stateleads to the different damage form of rail, and the residual stress has large effect on wearresistance, fatigue strength and fracture resistance, therefore, it is the key factor to cyclefatigue and mean stress. The stress distribution states of working rail are decided byresidual stress generated from rail manufacturing and the stress generated from the wheelrolling that is working on rail repeatedly.On the basis of considering the residual stress in the rail after straightening, this papermainly researches the changing mechanism of internal residual stresses of the rail underthe action of repeated rolling of the wheel. Using ANSYS software establishesthree-dimensional wheel-rail rolling contact model of more consistent with the actualsituation of the rail, and simulated calculations of wheel-rail rolling contact byANSYS/LS-DYNA explicit dynamic analysis program. To obtain changing mechanism ofthe internal residual stress of the rail, this paper establishes the rail length of5m, andselects two typical section of the rail, including the section in the middle of sleeper andthe section on the sleeper along longitudinal direction of the rail, to analyze the changingmechanism of the rail stress, which contains residual vertical stress, residual longitudinalstress, residual equivalent stress. Under repeated rolling action of the wheel, the authorestablishes the model include a wheel, two wheels, three wheels until ten wheels model,and carries out respectively simulation analysis to get the conclusion that residual stress ofthe rail is basically stable after the effect of the seven rounds. Under the effect of differentaxle load (25T、30T、35T), the author establishes a three-dimensional wheel-rail rollingcontact model include seven wheels, and carries on the comparison of differentsimulations, then analyzes the changing mechanism of residual stress of the rail under thedifferent axle load, thus concludes that the changing mechanism of residual stress of theentire rail in the causative process.The paper reveals the changing mechanism of residual stress causing by the wheelsrolling in the process of rail manufacturing, and it achieves the comprehensive andsystematic cognition of generation, changing and influencing factors of rail’s residualstress in the process of manufacturing to using. The paper provides scientific basis onrail’s stress state for the furthermore research of fatigue and fracture.