• Title, Summary, Keyword: wheel rail contact

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Calculating the Contact Stress Resulting from Lateral Movement of the Wheel on Rail by Applying Hertz Theory

  • Ashofteh, Roya Sadat
    • International Journal of Railway
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    • v.6 no.4
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    • pp.148-154
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    • 2013
  • This article has tried to review the maximum contact stresses in the contact area of the wheel and rail as a result of lateral movement of the wheel on rail by taking advantage from Hertz theory. Since wheel movement on rail is accompanied by lateral movement due to wheel profile conisity, so the contact point of wheel and rail is not constant and the contact stresses are therefore changeable in every single moment. Since the shape of rail profile and rail inclination, wheel diameter and the mechanical properties of the wheel and rail are effective on the stresses of contact area, these parameters have been studied by applying Hertz theory. This article aims to calculate the contact stresses in different parts on the wheel surface by using Hertz theory.

Wheel-Rail Contact Analysis considering the Deformation of Wheel and Axle (차륜 및 차축의 변형을 고려한 차륜-레일 접촉해석)

  • Choi, Ha-Young;Lee, Dong-Hyong;You, Won-Hee;Lee, Jong-Soo
    • Journal of the Korean Society for Precision Engineering
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    • v.27 no.8
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    • pp.20-27
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    • 2010
  • A precise evaluation of the contact position and the distribution of contact pressure in a wheel-rail interface analysis is one of the most important procedures to predict fatigue life and wear of wheel and rail. This paper presents the analysis result of finite element method(FEM) to investigate how the deformation of a wheelset, which is the assembly of wheel and axle of a railroad vehicle, affect the contact analysis of wheel and rail. 3D-FEM was used to analyze three contact models; a model with only wheel, a model with wheelset, and a model with simplified wheel and rail geometry. The analysis result of the contact position and the distribution of contact pressure are discussed. It is shown that the analysis results of a model with wheelset represent largest value with respect to contact pressure and contact stress. Furthermore, it is found that the distribution of contact pressure and the contact position is highly affected by the deformation of wheel and axle. It is concluded that the deformation of axle should be considered to evaluate the exact contact parameters in a wheel-rail contact analysis.

A Study on the Characteristics of the Wheel/Roller Contact Geometry (차륜/궤조륜 기하학적 접촉특성에 관한 연구)

  • Hur, Hyun-Moo
    • Journal of the Korean Society for Railway
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    • v.9 no.5
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    • pp.618-623
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    • 2006
  • Understanding the contact between wheel and rail is a starting point in railway vehicle dynamic research area and especially analysis for the contact geometry between wheel and rail is important. On the one hand, the critical speed as the natural characteristics of rolling-stock is generally tested on the roller rig. The geometrical characteristics of the wheel/roller contact on the roller rig are different from these of the general wheel/rail contact because the longitudinal radius of roller is not infinite compared with rail. Thus, in this paper we developed the algorithm to analyze the wheel/roller contact geometry of our roller rig which is constructed now and analyzed the difference between whee/roller contact and wheel/rail contact. In conclusion, we found that the yaw motion of wheelset and the roller radius influence the geometrical contact parameters in wheel flange contact area.

Tribological Approach on the Stress Distribution of Wheel-Rail Contact (차륜과 레일 사이의 접촉응력에 관한 트라이볼로지적 해석)

  • 황재용;김기환;김청균
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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    • pp.210-217
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    • 1997
  • This paper presents the numerical results of the stress analysis of wheel-rail contact problems. Two models which have straight and tapered(1:20) contact geometries between the wheelset and rail are analyzed using the finite element approach. From the simulation results we found that the tapered geometry of wheel-rail contact base line showed very stable contact stress distributions for a whole contact position between the wheel and rail in a curved rail section. The FEM computed results may present an optimized geometry of wheel-rail contact in a high-speed railway system.

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An Analysis on the Variation of the Wheel/Rail Contact Geometry with the Wheel Wear of EMU (전동차 차륜 마모에 따른 차륜/레일 기하학적 접촉 특성 변화 분석)

  • Hur, Hyun-Moo;Park, Joon-Hyuk;You, Won-Hee;Park, Tae-Won
    • Proceedings of the KSME Conference
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    • pp.854-859
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    • 2008
  • In a railway vehicle, contact between wheel and rail is a peculiar characteristic and variations of wheel and rail profile influence on the dynamic characteristics of railway vehicle. Thus the variations of the wheel and rail profile are very important in railway dynamics. Recently a research relating to active steering to improve the curving performance of vehicle is progressing actively at home and abroad. In this field, a pre-study for the wheel/rail contact geometry is needed and especially the variation of the wheel/rail contact geometry with wheel wear is the key design parameter to develop the controller of the active steering bogie. In this paper, we have experimentally studied to analyze the variation of the wheel/rail contact geometry with wheel wear as a pre-study to develop the active steering bogie for electric multiple unit (EMU). For this, we have made an experiment with EMU operating in curving area. We have measured the wear profiles of the wheel of the test vehicle and analyzed the wheel/rail contact geometry with a mileage of the test vehicle. In experiment with test vehicle, we have got the useful data to design the steering controller of the wheelset.

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A Study on the Contact Behavior of Stress-Displacement Characteristics for an Inclined Rail-Wheel Contact Mode (레일-휠의 접촉면 경사도에 따른 응력-변위량의 거동특성에 관한 연구)

  • 김청균
    • Journal of the Korean Society for Railway
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    • v.7 no.3
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    • pp.186-192
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    • 2004
  • Using the finite element method, rail-wheel contact model has been analyzed for mechanical loads due to passengers and payload of the train. This paper presents an investigation on how tapered wheel and inclined rail surfaces affect the contact stress and displacement of rail-wheel contacting surface under mechanical loads. For a numerical analysis, the tapered faces of the wheel are considered as 2.5% and 5.5%. And two models of the tilted rail are also considered as 40:1 and 20:1 at the bottom of the rail. The computed results based on the contact stress and displacement FE analysis indicate that the tilting ratio of the rail, 20:1 with a tapered face of the wheel, 2.5% may be more stable compared to that of 40:1 tilting model and 5.5% tapered wheel face.

Analysis of 3-dimensional Wheel/Rail Contact Geometry Considering Wheelset Yaw Motion (휠 세트 Yaw 운동을 고려한 바퀴와 선로 사이의 3차원 접촉 기하 해석)

  • Kim, Do-Jung;Park, Sam-Jin
    • 한국기계연구소 소보
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    • pp.5-17
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    • 1985
  • Dynamics of railway vehicles are strongly influenced by the wheel/rail contact forces. Wheel/rail contact geometric characteristics are important parameters to determining wheel/rail contact forces. In general, geometric relations between wheel and rail are represented by nonlinear functions of the wheelset lateral excursion and the relative yaw angle. There are some analytical and experimental studies to show the influences of the wheelset lateral displacement on wheel/rail geometric relations. Recently radial steering bogie which is designed to have flexible yaw motions of wheelsets was developed to improve curve negotiation performance. The radial steering bogie makes it important problem to study the effects of wheelset yaw motion on wheel/rail geometric relations. This paper describes the method to analyze 3-dimensional wheel/rail contact geometry considering wheelset yaw motion and describes also some computer simulation results.

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Developement of the Wheel-Rail Contact Algorithm and Dynamic Analysis (휠-레일 접촉 알고리즘 개발 및 동역학 해석)

  • Cho, Jae-Ik;Park, Tae-Won;Yoon, Ji-Won;Kim, Ji-Young
    • Proceedings of the KSR Conference
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    • pp.963-969
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    • 2010
  • The railway vehicle consists of wires, bodies, bogies and wheelsets, and each part has very complex mechanism. In this paper, wheel-rail contact algorithm is implemented using C++ and inserted into the ODYN which is a dynamic analysis program. To analyze wheel-rail contact mechanism, information such as contact points, contact angle and rolling radius is calculated according to the wheel and rail profile. Using this information, a table for the calculation of the wheel-rail contact analysis is made according to the lateral displacement. And, the creepage and normal force are calculated and a creep force is estimated by the FASTSIM. To verify the reliability of the wheel-rail contact algorithm, results of the program are compared with the ADAMS/Rail and paper. Finally, a wheelset of the railway vehicle is modeled using ODYN and simulated static and dynamic analysis. And, to verify the reliability of the simulation results, a displacement, velocity, acceleration and force are compared with results of ADAMS/Rail.

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Finite Element Analysis on the Stress Distributions in Rail-Wheel Contacts of High Speed Trains (고속전철용 레일-휠 접촉에서 응력분포에 관한 유한요소해석)

  • 김청균;김기환
    • Tribology and Lubricants
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    • v.13 no.3
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    • pp.93-101
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    • 1997
  • The numerical results on the stress distributions of rail-wheel contact problems are presented for three models in a high-speed rail system. These models which have straight and tapered (1:40 and 1:20) contact geometries between the wheelset and rail are analyzed using the finite element approach. From the simulation results we found that the tapered geometry (1:20) of railwheel contact base line showed very stable contact stress distributions for a whole contact position between the wheel and rail in a curved rail section. The FEM computed results may present an optimized slope geometry of rail-wheel contact in a high-speed railway system.

A Computational Efficient General Wheel-Rail Contact Detection Method

  • Pombo Joao;Ambrosio Jorge
    • Journal of Mechanical Science and Technology
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    • v.19 no.spc1
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    • pp.411-421
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    • 2005
  • The development and implementation of an appropriate methodology for the accurate geometric description of track models is proposed in the framework of multibody dynamics and it includes the representation of the track spatial geometry and its irregularities. The wheel and rail surfaces are parameterized to represent any wheel and rail profiles obtained from direct measurements or design requirements. A fully generic methodology to determine, online during the dynamic simulation, the coordinates of the contact points, even when the most general three dimensional motion of the wheelset with respect to the rails is proposed. This methodology is applied to study specific issues in railway dynamics such as the flange contact problem and lead and lag contact configurations. A formulation for the description of the normal contact forces, which result from the wheel-rail interaction, is also presented. The tangential creep forces and moments that develop in the wheel-rail contact area are evaluated using : Kalker linear theory ; Heuristic force method ; Polach formulation. The methodology is implemented in a general multibody code. The discussion is supported through the application of the methodology to the railway vehicle ML95, used by the Lisbon metro company.