Study On Effects Of Wheel Polygonalization And Countermeasures For High Speed Train

The High speed train operates on the high speed railway line through the rolling contact between the wheel and rail,and its dynamic performances are highly dependent upon the wheel/rail rolling contact condition.The wheel/rail rolling contacts,however,contribute to the wear generation on the wheel,which could lead to a wheel out-of-round(OOR)in the service.Such uneven wear can give rise to high magnitude impact loads at the wheel/rail interface and further pose significant influences on the dynamic performances and running safety of the vehicle.The polygonal wear of wheel is a kind of periodic uneven wear around the wheel circumference,which can lead to very high frequency and high magnitude impact loads at the wheel/rail interface.Whereas,the formation mechanisms of such wear have not yet been understand.It is thus desirable to study on the countermeasures to suppress and control the influences of wheel polygonalization,which also serves as the primary motivations of this study,as follows:(1)Survey the wheel application condition and the polygonal wear of wheels in the service,and investigate the statistical data of wheel polygonalization to identify the relationship between the wheel polygonalization and the type of vehicle,wheel tread,wheel radius and mileages.(2)Formulate a coupled vehicle/track dynamic model integrating with a flexible wheelset model and a flexible slab track model,validate the proposed model via the field test measurements.Considering the measured polygonal wear profile as inputs,investigate the influences of wheel polygonalization on the dynamic responses of vehicle system in terms of wheel/rail contact forces,axle box acceleration,dynamic stresses developed in the axle shaft.(3)Propose countermeasures of wheel polygonalization via comparing the influences of different strategies on the development of wheel polygonalization experimental,including different re-profiling procedures,rolling depression for wheel tread to improve the hardness of wheel tread,wheel tread grinding device removing the uneven wear,and changing the wheel material.