Analysis Of Resilient Wheel-Rail Coupling Rolling In Urban Rail Transit

As a new means of transportation,urban rail transit provides convenience for people to travel safely.However,with the increase of the carrying amount,the friction operation between the wheel and the rail becomes increasingly complex,and the rail fracture,wheel irregularity,rail corrugation and other problems occur in the urban rail transit system,which greatly shorten the service life of the urban rail transit system and affect the safety of people’s travel.The research of wheel-rail coupling contact is the foundation of solving many problems of urban rail transit system and plays an important role in the development of urban rail transit.Based on Hertz contact theory and finite element method,this paper studies the wheel-rail contact problem.The main work is as follows:Based on the subway wheel with a radius of 420 mm and the standard rail of 60Kg/m,the two-dimensional rigid wheel-rail contact model and resilient wheel-rail contact model including rail joints were established,and the corresponding loads and boundary conditions were applied,and the results were analyzed and solved.The accuracy of the model is verified by two dimensional Hertz contact theory.The contact pressure,equivalent stress,elastoplastic deformation and other contact parameters in the wheel-rail contact were studied.The results shown that the contact pressure increases with the decrease of the distance between the contact point and the rail joint.The equivalent stress and plastic deformation of the rail changed obviously,but the equivalent stress of the wheel did not change significantly.The stress at the rail joint is tensile stress,and the sharp increase of tensile stress leads to the destruction of the rail joint.The use of rubber resilient wheel can effectively reduce the tensile stress and extend the service life of the rail.A three-dimensional wheel-rail rolling contact model including rail joint and wheel control node is established.Contact was added between the control node and the inner surface of the wheel in the wheel-rail coupling rolling contact model,contact was added between the wheel hub and the rail,and corresponding constraints were imposed on the wheel and rail,and the solution was analyzed.The accuracy of the finite element model is verified by the results of three dimensional Hertz theory.The wheel in the process of rolling wheel-rail contact stress,equivalent stress and elastoplastic deformation and the other wheel-rail contact parameters were studied.The results shown that the static analysis of the wheel-rail coupling contact model could not fully reflect the changes of wheel-rail contact parameters such as wheel-rail contact pressure,equivalent stress and elastoplastic deformation.In the process of wheel rolling,the contact pressure between wheel and rail gradually increased as the wheel got closer to the rail joint,and the shape of wheel and rail contact spot gradually developed from the initial regular polygon to the irregular shape.With the increase of time,the change trend of the equivalent stress of the rail and the elastic strain of the rail were basically the same,which first decreased sharply,then increased slowly,and then decreases slightly.In the process of wheel rolling,the equivalent stress of the wheel gradually increased,until the wheel was close to the rail joint,and the equivalent stress value of the wheel reached the peak.