• Title/Summary/Keyword: Wheel-rail

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Evaluation of Field Calibration Test on Rail for Train Wheel Force Measurement

  • Sim, Hyoung-Bo;Yeo, Inho
    • International Journal of Railway
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    • v.8 no.1
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    • pp.1-4
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    • 2015
  • An accurate measurement of the train-track interaction forces is important for track performance evaluation. In the field calibration test as a wheel load measurement process, the calibration system creates a different boundary condition in comparison with that in the train wheel passage. This study aims to evaluate a reliability of the field calibration test in the process of wheel load measurement. Finite element models were developed to compare the deformed shapes, bending moment and shear force profiles on the rail section. The analysis results revealed that the deformed shapes and their associated bending moment profiles on the rail are significantly different in two numerical simulations of the calibration test and the train wheel load passage. However, the shear stress profile on the rail section of the strain gauge installation in the field was almost identical, which may imply that the current calibration test is sufficiently reliable.

The development of wheel-rail contact module for the next generation express train (차세대 고속철 해석을 위한 훨레일 모듈 개발)

  • Yoon, Ji-Won;Park, Tae-Won;Lee, Soo-Ho;Cho, Jae-Ik
    • Proceedings of the KSR Conference
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    • 2009.05b
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    • pp.225-230
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    • 2009
  • From the view point of railway vehicle dynamics, the interaction between wheel and rail have an huge effect on the behavior of the vehicle. This phenomenon is an unique motion, only for railway vehicles. Furthermore, close investigation of the backgrounds of the interaction is the key to estimate the dynamic behavior of the vehicle, successfully. To evaluate the model including flexible bodies such as car body and catenary system of the next generation express train, it is necessary to develop proper dynamic solver including a wheel rail contact module. In this study, wheel-rail contact module is developed using the general purpose dynamic solver. First of all, the procedure for calculation of the wheel-rail contact force has been established. Generally, yaw angle of the wheelset is ignored. Sets of information are summarized as tables and splined for further uses. With this information, normal force and creep coefficient can be extracted and used for FASTSIM algorithm, which has been shown good reliability over years. Normal force and longitudinal, lateral force at the contact surface are also calculated. Those data are verified by commercial railway simulation program 'VAMPIRE'. This procedure and program can offer a basic process for estimation of the dynamic behavior and wear of the wheel-rail system, even while running on the curved rail. Finally, multi-dimensional inspection tool will be developed including the prediction of the derailment.

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Research for a factor affecting creep force at Wheel/Rail contact surface of Roller Rig (모의주행성능시험기의 차륜/레일 접촉부 CREEP FORCE에 미치는 영향 인자에 대한 연구)

  • Jeon, Seung-Woo;Koo, Dong-Hoe;Kim, Jae-Chul;Hwang, Seok-Youl
    • Proceedings of the KSR Conference
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    • 2008.11b
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    • pp.606-612
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    • 2008
  • Creep force is one of the only appeared at conventional train which used to be driven by metallic wheel and rail contact. Due to the elastic deformation of wheel/rail contact patch by the weights of wheel and all the components related to it, creep force generates and becomes to the decision factor of critical speed of bogie(or railway vehicle) which is the criteria of avoiding vehicle to be unstable. There are many kind of factors which affect generation of creep force at a wheel/rail contact surface such as viscosity of contact patch, velocity, wheel and rail geometric profile, mechanical properties of wheel and rail. This paper concentrates on a wheelset simple 2 DOF Equation of Motion being exerted. From the simple numerical analysis using linear solution about getting creep force some factors could find roughly. Among the factors geometric parameter could be the one of most important for this study. In the future we'll prolong the range of study to find out method of measuring creep force easily.

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Development of a Wheel/Rail Geometric Contact Simulation Program (차륜/레일 기하학적 접촉 시뮬레이션 프로그램 개발)

  • 한형석;이은호;김재철
    • Journal of the Korean Society for Railway
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    • v.6 no.1
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    • pp.58-65
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    • 2003
  • Wheel/Rail geometric constraint relationships, such as effective conicity and gravitational stiffness, strongly influence the lateral dynamics of railway vehicles. In general, these geometric contact characteristics are nonlinear functions of the wheelset lateral displacement. There is a need to develop a wheel/rail geometric contact simulation program for wheels and rails with arbitrary profiles for the prediction of the dynamic behavior of railway vehicles. An algorithm to simulate any combination of wheels and rails is employed and a GUI for easy analysis is constructed. The simulation program is applied to KTX which will run on both KTX and conventional rails, two rail standards having different rail profiles. The results show that the two rail systems have different geometric contact characteristic

A Study on Wheel Noise Reduction Device for Railway Vehicle (철도차량 운행시 차륜방사소음 저감장치에 관한 연구)

  • Lee, Byoung-Chul;Lee, Jin-Young;Ho, Kyoung-Chan;Lee, Yong-Hyun;Kim, Gun-Young
    • Proceedings of the KSR Conference
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    • 2010.06a
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    • pp.1011-1016
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    • 2010
  • The noise emitted during train operation is generated with various reasons. It is known that the major noise generation is classified according to the ranges of train speed; that is, engine noise at lower speed range, rolling noise at medium speed range, and air-borne noise at higher speed range. These noises are transmitted in combined form with the noises generated from track components and under-carriage, etc. The rolling noise as a major noise at medium speed range is caused by the vibration occurred at wheel/rail interface. The vibration occurred at wheel/rail interface is transmitted to wheel and rail, and this vibration is emitted from wheel and rail as a noise. The object of this study is to investigate the effect of wheel damper of low noise wheel. In this study theoretical and experimental analysis is performed by numerical model calculations and impact test.

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Correlation Analysis between Dynamic Wheel-Rail Force and Rail Grinding (차륜-레일 상호작용력과 레일연마의 상관관계 분석)

  • Park, Joon-Woo;Sung, Deok-Yong;Park, Yong-Gul
    • Journal of the Korean Society for Railway
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    • v.20 no.2
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    • pp.234-240
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    • 2017
  • In this study, the influences of rail surface roughness on dynamic wheel-rail forces currently employed in conventional lines were assessed by performing field measurements according to grinding of rail surface roughness. The influence of the grinding effect was evaluated using a previous empirical prediction model for dynamic wheel-rail forces; model includes first-order derivatives of QI (Quality Index) and vehicle velocity. The theoretical dynamic wheel-rail force determined using the previous prediction equation was analyzed using the QI, which decreased due to rail grinding as determined through field measurements. At a constant track support stiffness, an increase in the QI caused an increase in dynamic wheel-rail forces. Further, it can be inferred that the results of dynamic wheel-rail analysis obtained using the measured data, such as the variation of QI due to rail grinding, can be used to predict the peak dynamic forces. Therefore, it is obvious that the optimum amount of rail grinding can be determined by considering the QI, that was regarding an operation characteristics of the target track (vehicle velocity and wheel load).

Analysis of Rail Wear Rate according to Wheel/Rail Contact Pressure on Curved Track (곡선부 차륜/레일 접촉압력에 따른 레일마모진전 경향 분석)

  • Sung, Deok-Yong
    • Journal of the Korean Society for Railway
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    • v.20 no.4
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    • pp.512-520
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    • 2017
  • On a typical railway, trains travel using the friction between the wheel and the rail. Contact pressure is generated between the wheel and the rail, and the magnitude of the contact pressure changes depending on the weight, speed, wheel-set hunting, and contact point of the vehicle. In this study, the contact characteristics were analyzed through the finite element analysis for the wheel/rail system on curved track, and fatigue damage and wear rate of wheel/rail according to contact pressure were analyzed through rolling contact fatigue test. Results indicate that, general and heat treated rails showed higher wear rate than wheels, and general and heat treated rail wear rate increased rapidly over a certain number of repetitions. In addition, the general rail wear rate was about 7 ~ 15% higher than that of the heat treated rail, and a regression equation for the rail wear rate with the contact pressure in the contact pressure range of 900 ~ 1,500 MPa was presented.

A Study on Dynamic Modeling and Analysis of a Wheelset (휠셋의 동역학 모델링 및 해석에 관한 연구)

  • Kang, Ju-Seok
    • Proceedings of the KSR Conference
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    • 2011.10a
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    • pp.1851-1855
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    • 2011
  • The accuracy of wheel-rail contact analysis is mainly determined by the methods to find wheel-rail contact points and to calculate contact forces. The 2-dimensional approach which calculates contact points based on the profile curves of the wheel and rail has advantage of reducing calculation time but shortage of approximating the solutions when comparing with 3-dimensional analysis In this analysis, wheelset dynamic behaviors calculated by the approach based on the 2-dimensional wheel-rail curves are compared with those by the 3-dimensional wheel-rail surfaces. Yaw angle and lateral displacement of wheelset center are compared when negotiating a curve.

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Railway vehicle dynamic analysis using an 3-dimensional wheel-rail contact analysis (3차원 휠-레일 접촉해석을 이용한 철도차량 동역학 해석)

  • Kang, Ju-Seok
    • Proceedings of the KSR Conference
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    • 2010.06a
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    • pp.18-24
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    • 2010
  • Conventional methods for railway vehicle dynamic analysis have mostly relied on the approximate method based on 2-dimensional contact analysis. Recently, 3-dimensional approaches to achieve an accurate solution for wheel-rail contact analysis have been proposed, but are not practical to apply to actual simulation due to time-consuming processes. The main focus of this study is to present a new method of railway vehicle dynamic analysis by calculating wheel-rail contact forces based on efficient 3-dimensional wheel-rail contact analysis. A 3-dimensional wheel-rail contact analysis and numerical analysis of wheelset dynamic equations will be presented.

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An Effect on Braking Force for Degradation of Rail Surface in the Urban Railway (도시철도에서 열차제동하중이 레일표면 열화에 미치는 영향)

  • Yang, Tae-Kyoung;Oh, Hee-Wan;Sung, Deok-Yong;Choi, Jin-Yu;Park, Yong-Gul
    • Proceedings of the KSR Conference
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    • 2011.10a
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    • pp.2135-2146
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    • 2011
  • The rail surface irregularity is generated severely by train braking effect in the section of station. The braking force increases slip rate and friction factors caused by wheel-rail contact points. It brings rail surface irregularity as well. In this study, interactions between wheel and rail were investigated using rolling contact fatigue theory and mechanism of rail degradation through fracture mechanics. For the more, the Von-Mises stress occurred on the rail due to the interaction between wheel and rail was analyzed using 3-D finite element method. The amounts of surface irregularity of rail were measured according to accumulated passing tonnage in urban railway in fields. Therefore, the maintenance of rail should be separated by running and braking sections to prevent RCF defects.

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