Research On The Profiles Matching And Wear Prediction Of Fixed Frog Used In Heavy Haul Railway

Heavy load,heavy axle and high density are the transport modes,which make the rail injury severely.In particular,the inevitable problem of "harmful space" makes the fixed frog damage more severely than common rail,and the maintenance increased dramatically.However,there is limited sky window on account of the high density characteristics of heavy haul railway transportation.The frog couldn’t get the system maintenance.With the increasing development of heavy haul railway,it is an important problem to study the wear mechanism of fixed frog and the matching of wheel and frog in the research field of wheel-rail relationship.According to the reference research data of vibration theory and turnout dynamics at home and abroad,locomotive,wagon and track of frog are viewed as an integrated system.Based on vehicle dynamics,turnout dynamics and finite element method,with wheel/rail relation on the frog as connection link,a simulation method is applied to study the dynamic characteristics of track in frog zone,comfort when passing the fixed frog and predict the nose rail of fixed frog.That provide certain theoretical basis and guidance for the profiles optimization and maintenance of fixed frog.Main research works are as follows:(1)The locomotive and wagon-fixed frog system dynamic models are established to analyze the change rules of the wheel-rail force,rolling circle,frictional power and creepage when locomotive and wagon passing the fixed frog.The "harmful space" makes the wheels impact on the nose rail when transfers from the wing rail to the nose rail,with the large wheel-rail vertical force,horizontal force and the friction power and the rolling circle radius mutating.The influence of wheel profiles on the vertical force and riding comfort when locomotive and wagon passing the fixed frog is studied.It is related to the height difference between the central section and outward of the wheel tread.The higher the height difference,the greater the vertical force,and the worse the smoothness when passing the frog.(2)The three-dimensional elastic-plastic contact finite element models of locomotive or wagon and fixed frog on the key positions are developed to research on the distribution of contact patches,equivalent stress and contact normal force and analyse the impacts of axle load and traction force on the longitudinal friction force,equivalent stress and contact status of wheel and frog.Based on the contact status of wheels with different profiles and the fixed frog,the contact paths of standard or worn locomotive and wagon wheels passing the standard or worn fixed frog is summed up to analyse the effect of profiles of wheel and frog on the contact position.The equivalent stress of dynamic load at different speeds is compared with that of static load.(3)A new frictional work computing method is put forward based on the theory of friction work.Wheel-rail wear prediction model is developed and the corresponding numerical procedure is programmed.The effect of locomotive and wagon,dynamic vertical force and the nonlinear properties of wheel-rail material on the wheel-rail abrasion is considered in the prediction model.Based on the finite element calculation results,the wear prediction of rail profile is conducted.The predicted profile is compared to the measured,and there is good fit.That verified the accuracy of the new wheel-rail wear prediction model.(4)The fixed frog wear prediction model is established to predict the profile of nose rail at 480mm distance from theoretical nose of crossing.And the influence of the wheel profiles of locomotive and wagon on the abrasion of nose rail is analyzed.The relationship between the maximum wear depth,abrasion area and the train throughput is obtained.The wear depth and loss of the nose rail at different positions of fixed frog is compared and the relation between the vertical height of nose rail and the train throughput is analyzed to master the evolution of the nose rail.