Study and Monitoring of Driving Forces that Arise at the Contact Point Between the Wheel Border and the Rail during the Motion of the Rail Vehicle on a Curved Path of the Railway Line (original) (raw)
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Revista Facultad de Ingeniería
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...
A new wheel–rail contact model for railway dynamics
Vehicle System Dynamics, 2007
The guidance of railway vehicles is determined by a complex interaction between the wheels and rails, which requires a detailed characterization of the contact mechanism in order to permit a correct analysis of the dynamic behavior. The kinematics of guidance of the wheelsets is based on the wheels and rails geometries. The movement of the wheelsets along the rails is characterized by a complex contact with relative motions on the longitudinal and lateral directions and relative rotations of the wheels with respect to the rails. A generic wheel-rail contact detection formulation is presented here in order to determine online the contact points, even for the most general three dimensional motion of the wheelset. This formulation also allows the study of lead and lag flange contact scenarios, both fundamental for the analysis of potential derailments or for the study of the dynamic behavior in the presence of switches. The methodology is used in conjunction with a general geometric description of the track, which includes the representation of the rails spatial geometry and irregularities. In this work the tangential creep forces and moments that develop in the wheelrail contact area are evaluated using alternatively the Kalker linear theory, the Heuristic nonlinear model or the Polach formulation. The discussion on the benefices and drawbacks of these methodologies is supported by an application to the dynamic analysis of the bogie of the railway vehicle.
An investigation into the effect of train curving on wear and contact stresses of wheel and rail
Tribology International, 2009
Some important papers concerning the studies on rail wear and wheel/rail contact stresses are briefly reviewed. The present paper utilizes a numerical method to analyze the effect of railway vehicle curving on the wear and contact stresses of wheel/rail. The numerical method considers a combination of Kalker's non-Hertzian rolling contact theory, a material wear model and a vertical and lateral
An Investigation Into Effect of Train Curving on Wear and Contact Stresses of Wheel and Rail
Volume 2: Automotive Systems; Bioengineering and Biomedical Technology; Computational Mechanics; Controls; Dynamical Systems, 2008
Some important papers concerning the studies on rail wear and wheel/rail contact stresses are briefly reviewed. The present paper utilizes a numerical method to analyze the effect of railway vehicle curving on the wear and contact stresses of wheel/rail. The numerical method considers a combination of Kalker's non-Hertzian rolling contact theory, a material wear model and a vertical and lateral coupling dynamics model of the vehicle/track. In the analysis, the important factors influencing on the wear and the contact stresses are, respectively, the curving speed, the curved track super-elevation and the rail cant. Compared to the present model, some concerned models and results in the published papers are in detail discussed. Through the detailed numerical analysis, it is found that the difference between the normal loads of the left and right of the wheelset increases linearly with increasing the vehicle curving speed. The material wear volume per length along the rail running surface has a tendency to grow. However, the variation of the maximum normal contact stress has a large fluctuation as the curving speed increases. The increase of the maximum contact stress depends greatly on not only the normal load but also the profiles of the wheel/rail. Increasing the track super elevation efficiently lowers the normal load difference of the left and right of the front wheelset, and the contact stresses and the wear. The rail cant has a great influence on the low rail wear of the curve track. An increase in rail cant results in a great increase in the low rail wear of the curved track, and a decrease in the outside rail wear. These conclusions are very useful in the maintenance of the track.
Peculiarities of Traction Forces in Wheel/Rail Contact Area
TRANSPORT
Tractive force and train movement stability dependence on division of forces involved in wheel/rail contact area are the main subjects of this article. The influence of wheel/rail contact properties in the vehicle dynamics and adhesion fields is investigated. Current tendency all over the world is to reduce the conicity of wheels with the aim of increasing the speed of trains. Wave-length of moving wheel-set in track for worn wheel-set tyre is twice less than for new wheel running profile.
This paper deals with a possibility of reduction of guiding forces magnitude in small-radius curves by means of active elements. These guiding forces characterize the lateral force interaction between the rail vehicle and the track and influence the wear of wheels and rails in curves. Their magnitudes are assessed in the framework of vehicle authorization process. However, in case of new railway vehicles with axleload of approximately 20 t and more it is problematic to meet the condition of maximum value of the quasistatic guiding force which acts on the outer wheel of the 1 st wheelset in small-radius curves. One of the possible ways how to reduce these forces is using the system of active yaw dampers. By means of computer simulations of guiding behaviour of a new electric locomotive, comparison of reached values of the quasistatic guiding forces in case of locomotive equipped with active yaw dampers and without them was performed. Influences of magnitude of force generated by the ...
Evaluation of the Influence of a Rail Vehicle Running with Wheel-flat on the Railway Track
LOGI - Scientific Journal on Transport and Logistics
The railway transport network is currently in a quite big expansion. Therefore, railway tracks are modernized and the attention is given also on the technical state of rail vehicles, which operate on them. However, it may happen that the wheel surface is damaged. One of the most common reasons of wheel damage is too much braking, which results to the wheel-flat formation. This article is focused on the evaluation of the influence of a rail vehicle running on the railway track, which a wheel is damaged by the wheel-flat. Investigation of these negative effects was performed by means of simulation computations. As evaluating parameters, values of the wheel force in the contact of the rail and wheel with a flat where observed.
Influence of Wheel Profiles on Rolling Contact Fatigue and Wear Rate of Railway Wheels
Wheels and rails provide guidance of a rail vehicle on a track. For that reason wheels and rails have dominant influence on safety against derailment and running performance of a railway vehicle. The wheel and the rail profiles also have significant influence on the wheel/rail wear, surface damage, forces in the contact between wheel and rail, track shift forces, as well as on track and wheelsets maintenance. This paper presents the influence of different combinations of wheel and rail profile on rolling contact fatigue and wear rate of rail wheels. Simulations behaviors of a vehicle were performed for six different combinations of wheel and rail profiles with different rail inclinations, on straight track and in a curve, assuming ideal track without track irregularities. The set of combinations includes theoretical profiles of wheel and rail S1002/UIC60i40, S1002/UIC60i20 as well and worn profiles P8/UIC60i40, P8/UIC60i20, WP4/BV50i30 and WP4/MB1BV50. INTRODUCTION In the last decad...
Computers & Structures, 2011
Nowadays, one of the most sensible issues in the railway industry is the damage on vehicles caused by the track conditions and the infrastructure deterioration due to the trains' passage. Therefore, it is essential to acquire a better understanding on how the operation conditions influence the wear evolution of the railway wheels and the consequences of their changing profiles on vehicle-track interaction forces. In this work, a computational tool is used to simulate the dynamic performance of integrated railway systems and to predict the wear evolution of wheel profiles. The tool is applied to realistic operational scenarios with the purpose to evaluate the influence of the track conditions, defined by the track geometry and by its irregularities, on the wear progression of railway wheels. The loads imposed to the railway infrastructure by a trainset running at different velocities, on a track with and without irregularities, and equipped with wheelsets having new and worn profiles is also studied. The studies performed here show that the levels of track irregularities considered have a negligible influence on the wear progression. Furthermore, the loads imposed to the track during trainset operation are not affected by the wear state of the wheels. On the other hand, the track imperfections can affect significantly the vehicle-track interaction forces.