A Study On Wheel/Rail Rolling Contact Theory Based On Finite Element Method And Its Applying

The development tendency of the railway construction in the world today is serving high speed trains and carrying heavy load. With the development some problems of the wheel/rail performance arises, and the requirement of the train traction for the adhesion of wheel/rail will become more and more strict, and wheel/rail wear, rolling contact fatigue, derailment and noise will become more and more serious. The solution to the problems will have direct effects on the railway development. Although the investigations in the problem are concerned with many disciplines, they are based on the theory of wheel/rail rolling contact.The theory of wheel/rail rolling contact is used to study the statement of wheel/rail relative motion and contact force on contact patch as a train running. Chapter 2 gives detailed derivation of a few typical theoretical models of rolling contact with Hertzian form, which are widely used in the dynamical analysis of railway vehicle at present. And the chapter gives Kalker's theory of three-dimensional elastic bodies in rolling contact with non-Hertzian form, which was completed by the 1990s. But Kalker's theory has not broken the limit of elastic half space assumption, which can not be used to make further investigation in the problem of complicated wheel/rail reaction.Lots of engineering applications demonstrate that the finite element method (FEM) is an advanced and efficient method in solving wheel/rail rolling contact problems. In this paper, a wheel/rail rolling contact finite element model based on Arbitrary Lagrangian Eulerian(ALE) is established and applied to the wheel/rail steady state rolling contact analysis. The adhesion condition of no shear slip velocity is applied by Lagrange multiplier method in the ALE contact weak form, by which method the adhesive character on contact patch is accurately calculated. A three-dimensional wheel/rail transient rolling contact FEM model based on Lagrangian FEM is established and used in the simulation of wheel/rail dynamic rolling contact process. The implicit and explicit FEM have been coupled to simulate wheel/rail rolling contact process. By these methods, stabile results are obtained in short time for the wheel/rail rolling contact. The nonlinear material constitutive model, nonlinear contact shape, rolling velocity of the wheel and inertia force are considered in the models. These methods have broken the limit of Hertz contact conditions and elastic half space assumption, and the methods make the wheel/rail rolling contact problems really become into a dynamic problem.In this paper, the wheel/rail rolling contact FEM model based on ALE FEM is applied to analyse a wheelset steady state rolling contact on a rail. The contact stress,friction shear stress and relate slip velocity in the contact patch are analyzed by the method. Kalker's theory of three-dimensional elastic bodies in rolling contact with non-Hertzian form is applied to analyse a wheelset rolling contact on a rail. The numerical results of the two methods are compared.In this paper, the adhesion condition of no shear slip velocity is applied by Lagrange multiplier method in the ALE steady state rolling contact FEM model. The model is used to analyse the creep force characteristic curve in dry friction condition. The adhesion condition of no shear slip velocity is applied by penalty method in the ALE steady state rolling contact FEM model. In this model, penalty method may be thought of as a regularization of the contact interface condition, and the regularization can smooth Coulomb fiction by importing coarseness. Effect of slip tolerate on the creep force characteristic curve is discussed.A wheel/rail profile wear prediction methodology based on three-dimensional transient wheel/rail rolling contact is presented. The wear model and adaptive mesh adjustment technique are important techniques for numerical method of wheel/rail wear. The integral form of Archard wear model is obtained, which is based on tiny area and is suited to FEM. Laplacian smoothing with area weights is used to smooth the meshes of wheel and rail. The wear method is applied to the wheel/rail disc test about the wear of flange and gauge. The simulation results are compared with measurements of Laboratory wear test and verify the effectiveness of wear prediction methodology. Based on the wheel/rail steady state rolling contact analysis, a wheel profile wear prediction methodology is developed and applied to the wheel wear when the heavy haul train passes in curved track with the small radius. In the loop of the prediction methodology, the vehicle dynamics model is built by the ADAMS software and the forces of the bearing boxes from the vehicle system dynamics model are loaded on the model of three-dimensional nonlinear finite element steady state analysis for wheelset rolling contact process.