This paper introduces a new computer program called WEAR. It contains a new and more accurate method for calculating wheel–rail contact stresses to predict degradation due to wear, deformation and fatigue. WEAR accounts for conformal contact by using influence numbers that are based on quasi-quarter spaces instead of the traditional half-spaces and considers the varying geometrical spin due to the varying contact angle through a contact patch. This new contact method is applied to two cases: wheel–rail contact in a turnout and conformal contact in a curve with a heavily worn wheel profile. In both cases, many of the assumptions commonly made in excising solution methods for wheel–rail contact problems, such as a small contact patch and a constant spin creepage, may be violated. The case of conformal contact demonstrates the effect of the influence numbers and the varying spin creepage on the resulting stresses and creep forces and provides a comparison of this new method with the well-established contact method CONTACT. For the turnout case, the first task is to obtain realistic input for all timesteps of a vehicle coasting through a turnout (i.e., diverging route) in a simulation. This step is necessary because the contact forces, which cause wear, deformation and fatigue of the wheels and rails, and the dynamics of the vehicle-turnout interaction strongly influence each other. WEAR converged for all timesteps, including many cases with multiple-point contacts at the switch blade and with extremely high creepages. This robustness demonstrates suitability of the new method for online contact force evaluation in vehicle dynamics simulations.

This paper presents a comparison of four models of rolling contact used for online contact force evaluation in rail vehicle dynamics. Until now only a few wheel–rail contact models have been used for online simulation in multibody software (MBS). Many more models exist and their behaviour has been studied offline, but a comparative study of the mutual influence between the calculation of the creep forces and the simulated vehicle dynamics seems to be missing. Such a comparison would help researchers with the assessment of accuracy and calculation time. The contact methods investigated in this paper are FASTSIM, Linder, Kik–Piotrowski and Stripes. They are compared through a coupling between an MBS for the vehicle simulation and Matlab for the contact models. This way the influence of the creep force calculation on the vehicle simulation is investigated. More specifically this study focuses on the influence of the contact model on the simulation of the hunting motion and on the curving behaviour.

La relación entre los desplazamientos de la rueda contenidos dentro del plano de contacto rueda-carril y presentes durante la circulación de un tren en tramos curvos, constituye uno de los problemas más importantes de la dinámica ferroviaria, modelado mediante un fenómeno físico complejo y no lineal. Con el propósito de analizar la dinámica de un vehículo ferroviario que se desplaza a lo largo de una curva, se ha desarrollado un modelo global que incluye la caracterización de la vía y de la fijación, las propiedades de rigidez y amortiguamiento de la suspensión del bogie y la identificación de las condiciones globales de la zona de contacto rueda-carril. El presente artículo describe una formulación analítica que permite estimar el estado dinámico debido al paso de un vehículo ferroviario, resumiendo los resultados y simulaciones derivadas de la aplicación de dicho modelo, bajo la premisa de que el contacto entre la rueda y el carril es constante, y por tanto, el giro de los ejes de...

Computer-aided simulation of the wheel-rail interaction was performed with the help of the program code "Universal Mechanism» and its version "UMWear", the tribodynamic model, enabling to find wheel or rail profile evolution due to wear. Specific features of wheel and the rail profiles' evolution model are described. The objectives of simulation are to find the influence of various track and vehicles parameters on wheel/rail interaction characteristics, such as wheel/rail friction work and wheel wear, contact parameters, temperature and safety factor characterizing derailment risk. Some conclusions on a degree of the influence are made.

The long history of railway engineering provides many practical examples of dynamic problems which are unique to railway vehicles. One of the railway vehicle's dynamic problems is the lateral dynamic which is mainly arising from wheel rail contact condition. In the early time, to analyze and formulate such kinds of railway vehicle dynamics scientists had been using different experimental methods such as roller rigs and roller coasters. Even though such experimental methods are most efficient and error free, they are very costly and need some time. But now a day there are different computer packages used to study and simulate the dynamic behavior of a railway vehicle (ADAMS/RAIL, SIMPAKC and Vampire). These computational packages are very efficient in both cost and time but they are not more flexible and require indepth knowledge to run them. So this paper tried to make the computational tool more flexible and easy to use with basic computer knowledge In the work presented, mathe...

Background: Mathematical modelling aids diagnostics the track and rolling stock, as it often for technical reasons it is not possible to obtain a co mplete set of measurement data required to diagnose the rail and wheel deformation caused by the impact of a rail vehicle on the track. The important issue in a railway diag nostics is to study the effects of contact wheel and rail. Diagnostics investigations of track and rolling stock have a fu ndamental role in ensuring the safety of transport of passengers and goods. The aim of the study presented in the paper was to develop simulation methods of mathematical modelling of the wheel- rail system useful in the diagnostics of the track and a railway vehicle. Methods: In the paper two ways of modelling were presented and discussed. One of these ways is the method which consists in reducing the contact issue to field iss ue and solving the identification of the field sour ce in 2-D system. Also presented a different method designed on the...