The Experimental Study Of Axle Weight And Foundation Stiffness On Wheel And Rail Sliding Friction

In recent years,china's support for high-speed railway construction has been increasing,and high-speed railway mileage has Develope high-speed rail construction and operation process,the foundation rigidity and load has a significant effect on high-speed rail wheel/rail wear,directly affecting the service life of high-speed operation,so how to achieve a reasonable foundation stiffness and reasonable load is very important.In view of this,this paper USES indoor dynamic load simulation test machine to test the different foundation stiffness and load,the contact stress of the wheel rail,the abrasion amount,the rail temperature and the surface damage.The main contents are as follows:(1)Theoretical analysis of contact characteristics of wheel and rail contact,contact mechanics,contact model and other contact characteristics,the ideal thermal model of wheel and rail sliding contact and the study of wheel and rail heat conduction.(2)Research on the structure of the experimental machine itself,such as the motion study,simulation criterion and simulation parameter selection.The practicability of dynamic simulation experiment machine is evaluated.(3)Determine the stiffness of the rubber cushion under different thicknesses,study the stiffness of the rubber cushion,and select the experimental stiffness.(4)Under the condition that other conditions remain unchanged,the influence of axle weight and foundation stiffness on rail contact stress,rail temperature,abrasion and surface damage is studied.Through the analysis of experimental data,the following conclusions are drawn:(1)With the increase of the axle weight,the vertical contact stress and dynamic load of the wheel and rail are constantly changing,and the friction between the wheel and the rail will become larger,and the rail will be easily damaged.When the impact frequency of the wheel is constant,the change of axle load has no effect on the frequency of dynamic load.When the axle weight is less than 16 t,the wheel and rail wear rate increases rapidly with the axial weight,and when the axle weight changes from 16 t to 21 t,the speed of wheel and rail wear decreases.When the axle weight is greater than 21 t,the speed of wheel and rail wear becomes larger as the axle weight becomes larger.Decreases as the axle load and rail wear zone width grows,cross ditch,wear area because of cross ditch,in the presence of rail contact surface along the direction of the relative sliding cross ditch and gravel,the friction surface bumps and deep pit density,rail of abrasive and adhesive wear heavier,rail friction surface abrasion become serious.(2)Decreases as the foundation stiffness,the normal contact force of wheel and rail and the dynamic load increases slightly,amplitude of the vertical impact between wheel and rail is larger,the stress of the steel rail will become more complex,this will speed up the rail damage,but the impact is very small.With the increment of the foundation stiffness,rail friction temperature in constant rise,because when the foundation stiffness unit foundation stiffness increases,for a greater influence on the dynamic load coefficient,wheel/rail stress change is big,the foundation stiffness is bigger,the unit foundation stiffness changes caused by the change of dynamic load coefficient is small,between wheel and rail pressure change is small,when the foundation stiffness gets to a certain value,the unit foundation stiffness changes to change the dynamic load coefficient is very small,negligible,so the temperature rise rate is lower.Within a certain range of foundation stiffness and foundation stiffness and rail abrasion is closely relative to the amount,as the stiffness and the wheel/rail contact area change rate constant decreases,and the local damage evolution slower,but abrasion value growth rate is reduced.As the stiffness of the simulated foundation increases,the width of the scratch is narrowed.Wear the cross ditch phenomenon becomes more and more obvious,because of the reason of the cross ditch,on the rail surface along the direction of the friction of the trench and abrasive more and more,the rail wear surface damage degree increased.