• Title/Summary/Keyword: Wheelset

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A Study for behavior mode frequency of railway vehicle using ramp device (Ramp장치를 이용한 철도차량 거동모드 주파수에 관한 연구)

  • Yang, Hee-Joo;Woo, Kwan-Je;Seong, Jae-Ho
    • Proceedings of the KSR Conference
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    • 2010.06a
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    • pp.30-35
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    • 2010
  • The railway vehicle is a multi-body system running on the track which consists of carbody, bogie and wheelset, each of components is connected with rigid mass, spring and damper. each of components has translation motions of longitudinal (X axis), lateral(Y axis) and vertical(Z axis) direction, and rotation motions of X, Y, Z axis which are named Rolling, Pitching and Yawing. The vibration mode of railway vehicle is difficult to find the characteristics of motion during the operation on the track because these happen to independence or duplication motion caused by vehicle, wheel/rail and track irregularity etc. This paper presents the result of ramp test to show the bounce, roll, pitch and yaw mode frequency of the railway vehicle.

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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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The introduction of Speed Qualification Test as regulated by US CFR regarding railway running safety (철도차량 주행안전성관련 미국 연방법규(CFR)에 따른 본선 Speed Qualification Test 개요)

  • Lee, Kang-Wun
    • Proceedings of the KSR Conference
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    • 2010.06a
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    • pp.1-5
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    • 2010
  • The Hyundai Rotem company is due to be conducted the main line Speed Qualification Test as regulated by CFR for SEPTA EMU and SCRRA Bi-level coach project. The regulated test items per 49CFR213.345 are wheel/rail interaction forces and carbody/truck accelerations during running on main line. Therefore the special two sets of instrumented wheelset (IWS) per each project have been made for measuring the interaction forces between wheel and rail at four wheels of one truck during running on main line. In this paper, regarding Speed Qualification Test, the required test items and data analysis method per 49CFR213.345 and the preparation status of instrumented wheelsets (IWS) are introduced.

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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.

Analysis of Dynamic Characteristics of High Speed Trains Using a Time Varying Frequency Transform (시간-주파수 변환을 이용한 고속철도차량의 동특성 분석)

  • Lee, Jun-Seok;Choi, Sung-Hoon;Kim, Sang-Soo;Park, Choon-Soo
    • Proceedings of the KSR Conference
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    • 2008.06a
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    • pp.841-848
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    • 2008
  • This paper examined dynamic characteristics of high speed trains using a time varying frequency transform. Fourier transform based methods are frequently used for the calculation of the dynamic characteristics of trains in the frequency domain, but they cannot represent the time-varying characteristics. Therefore it is necessary to examine their characteristics using a time-varying frequency transform. For the examination, the non-stationary vibration of wheelset, bogie, and carbody are measured using accelerometers and stored in a data aquisition system. They are processed with localization of the data by modulating with a window function, and Fourier transform is taken to each localized data, called the short-time Fourier transform. From the processed results, time varying auto-spectral density, cross-spectral density, frequency response, and coherence functions have been calculated. From the analysis, it is confirmed that the time varying frequency transform is a useful method for analyzing the dynamic characteristics of high speed trains.

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Lateral Vibration Analysis of a Small Scale Railway Vehicle Model (축소형 차량의 횡진동 해석)

  • Lee Seung-Il;Son Gun-Ho;Choi Yeon-Sun
    • Proceedings of the KSR Conference
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    • 2004.10a
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    • pp.417-422
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    • 2004
  • The vibration of a running vehicle can be classified on lateral, longitudinal and vertical motions. The important factor on the stability and ride quality of a railway vehicle is the lateral motion. The contact between wheel and rail with conicity influences strongly on the lateral motion. In this study, an experiment for the vibration of a running railway vehicle was performed using a small scale railway vehicle model. Also, the effects on the car body, bogie and wheelset were examined for the weight and the stiffness of the first and second suspension. The experimental results showed that the lateral vibration increases as the wheel conicity and stiffness of the second suspension increase. And the lateral vibration of the bogie increases as the mass ratio between car body and bogie increases. Also, the lateral vibration of the wheel becomes high at low speed, while the wheel of 1/20 conicity makes severe vibration at high speed running.

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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

Analysis on the Snake Motion of One Freight Car for High Speed Running (고속주행을 위한 화차 한량의 사행동 해석)

  • 이승일;최연선
    • Journal of the Korean Society for Railway
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    • v.6 no.3
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    • pp.149-155
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    • 2003
  • The development of railway vehicles involves the proper selection of design parameters not only to achieve high speed but also to reduce the vibration of the train. In this study an analytical model of a freight car is developed to find the critical speed. The freight car can generate the snake motion of the lateral and yawing motion of the car body, the bogie, and the wheelset. Numerical analysis for the nonlinear equation motions with 17 degrees of freedom showed the running stability and critical speed due to the snake motion. Also, the vibration modes of the freight car was calculated using ADAMS/RAIL, which showed that the critical speed have the yawing modes of the car body and the bogie. Finally this paper shows that the snake motion of the vehicle can be controlled with the modifications of the design parameters.

A Study on the Factors Influencing the Non-Linear Stability of Railway Vehicles (철도차량의 비선형 안정성에 영향을 미치는 인자 연구)

  • Chung, Woo-Jin;Shin, Jeong-Ryol
    • Proceedings of the KSME Conference
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    • 2001.06b
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    • pp.513-518
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    • 2001
  • This research has been performed to estimate the hunting motion hysteresis of railway passenger cars. An old and a new car with almost same structure are chosen as analysis models. To solve effectively a set of simultaneous equations of motion strongly coupled with creep relations, shooting algorithm in which the nonlinear relations are regarded as a two-point boundary value problem is adopted. The bifurcation theory is applied to the dynamic analysis to distinguish differences between linear and nonlinear critical speeds by variation of parameters. It is found that there are some factors and their operation area to make nonlinear critical speed respond to them more sensitivity than linear critical speed. Full-scale roller rig tests are carried out for the validation of the numerical results. Finally, it is concluded that the wear of wheel profile and the stiffness discontinuities of wheelset suspension caused by deterioration have to be considered in the analysis to predict hysteresis of critical speed precisely.

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Estimation of Curving Performance and Running Safety of Gwangju Electric Multiple Unit for City Subway (광주도시철도 전동차의 곡선추종성 및 주행안전성 평가)

  • Ham, Young-Sam;Oh, Taek-Yul
    • Proceedings of the KSME Conference
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    • 2004.04a
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    • pp.745-750
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    • 2004
  • For the safety of railway, it should be evaluated for the running safety by measuring the derailment coefficient. Although railway has run the fixed and maintained rail, some of railway is derailed. This report shows the results that performed the static load test, wheelset manufacturing for test, main line running test on the basis of the derailment theory and experience. It is executed main line test into more than 80km/h for estimating the curving performance and running safety of Gwangju EMU. As the test results, could confirm the curving performance and running safety of Gwangju EMU from the results of the wheel unloading, lateral force, derailment coefficient etc. Derailment coefficient was less than 0.8, and lateral force allowance limit and wheel load reduction ratio were enough safe.

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