Research On Contact Vibration And Creep Characteristics Of High-speed Train Wheel-rail Based On MFBD

For wheel-rail system of high-speed train,the contact characteristics of wheel-rail change dynamically,showing a contact vibration form,that is,there is both contact and vibration,and this contact vibration is accompanied by the whole service process.In addition,the unique geometric features of the wheel-rail and the motion characteristics of wheelsets determine that the creep is inevitable in this process.The characteristics of wheel-rail creep directly affect the running performance of trains,and accurately grasping the creep characteristics is very important for the quality of train operation.At present,when studying the dynamic characteristics of wheel-rail contact vibration,Kalker theory and Fastsim algorithm are generally integrated in commercial dynamic software,such as Simpack,Adams or UM.Treating the wheel-rail as rigid bodies as usual,wheel-rail contact algorithm based on elastic half-space theory,which play important roles in solving static and steady problems of wheel-rail rolling contact.However,the contact dynamic response of wheel-rail system cannot be accurately analyzed without considering the influence of wheel-rail contact vibration and other factors.In fact,the wheel-rail rolling contact is a typical transient dynamic problem.Under the complex load,the contact interface will produce slight amplitude vibration in the direction of multi degree of freedom,showing the dual characteristics of energy storage and energy dissipation,both stiffness and damping.And it excites flexible characteristics,the flexible spring-damping contact model can more accurately reflect the vibration response and creep characteristics of wheel-rail rolling contact in accordance with the actual situation.In this paper,the research of flexible contact algorithm for high-speed wheel-rail system based on finite element multi-flexible body dynamics(MFBD)technique is first carried out,using a new generation of multi-body dynamics software RecurDyn,which breaks through the traditional flexible body modeling method,which is the fixed modal synthesis.Then take the S1002 CN wheel and CN60 rail as the research object,because the flexible wheel can reflect the elastic deformation and vibration in high speed rolling contact condition,the vehicle wheels and the track module are solid finite element flexibility.The contact stiffness-damping of wheel-rail are determined by reverse modeling of field test data,and a flexible contact model of high-speed wheel-rail based on spring-damping is established.Then,based on vehicle-track coupling dynamics theory,a numerical model of high-speed wheel-rail rolling contact spatial coupling vibration under flexible contact mechanism is built and verified.With this model,the rolling contact vibration characteristics of high-speed wheel-rail under different conditions including vehicle parameters(empty or loaded car,running speed,and primary suspension),track structure parameters(stiffness and spring of fasteners)and wheel rail interface state(wheel-rail contact stiffness,contact damping,constant and various friction coefficient)are studied.The spatial vibration behavior of wheel-rail concretely includes vibration acceleration,frequency,displacements and so on.The wheel rail creep phenomenon is associated with the whole wheel rail contact vibration process.The creep characteristic under vibration mechanism is worth further research.Based on this,the factors affecting the creep and creep force/rate of flexible wheel and rail are analyzed.A new idea is opened up for the accurate study of the creep and its characteristics of the rolling contact vibration of the high-speed wheel-rail.