• Title/Summary/Keyword: Wheelset

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Study on Mechanical Parameters of a Wheelset Influencing Derailment of Rolling Stock (철도차량탈선에 영향을 미치는 윤축의 기계적 인자에 관한 연구)

  • Oh, Hyun Sun;Koo, Jeong Seo
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.37 no.10
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    • pp.1207-1218
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    • 2013
  • It is difficult to predict derailment with the existing derailment coefficient like Nadal's formula which is based on the contact forces between one wheel and rail. A new derailment coefficient model developed on a wheelset is able to make a better estimate about the climb derailment, slip derailment, roll over derailment, and mixed derailment types of these. Moreover, not only the mechanical factors considered in the existing derailment coefficients but also other various factors affecting derailment such as wheel unloading and loading, diameter of wheel, and locations of axle-box bearings can be covered with this new derailment coefficient model. That is, the derailment patterns which couldn't be solved with the existing formulas such as Nadal's and Weinstock's models can be analyzed with this wheelset derailment coefficient model because of considering various factors causing derailment. Finally, the validity of the new derailment coefficient model is verified using dynamic model simulations.

Wheelset Steering Angle of Railway Vehicle according to Primary Suspension Property (철도차량 1차현가 특성에 따른 윤축 조향각 성능 분석)

  • Hur, Hyun Moo;Ahn, Da Hoon;Park, Joon-Hyuk
    • Journal of the Korean Society for Precision Engineering
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    • v.32 no.7
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    • pp.597-602
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    • 2015
  • In this paper, we studied the steering performance of wheelset with primary suspension characteristics of railway vehicle. We carry out dynamic analysis and experimental study for the vehicle models which are different primary suspension characteristics. The steering angle of a vehicle model (Case 1) operating in domestic subway lines is insufficient compared with an objective steering angle for curved track. And the steering angle of a vehicle model (Case 2) with improved self-steering performance of wheelset is a little improved compare to previous vehicle model. But also Case 2 model is still insufficient compared with an objective steering angle and has its limit in steering performance. So to overcome this limit of steering performance of passive type railway vehicle, an active steering technology is being developed. In case of vehicle model with active steering system, the steering performance is improved remarkably compared to passive type vehicle model.

Structural Analysis of Locking Parts in the Gauge -Adjustable Wheelset (궤간 가변 윤축의 잠금부품들에 대한 구조해석)

  • Kim, Chul-Su;Chang, Cheon-Soo;Jang, Seung-Ho;Kim, Jung-Kyu
    • Journal of the Korean Society for Railway
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    • v.11 no.1
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    • pp.33-38
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    • 2008
  • To reduce the cost and time of transport in Eurasian railroad networks such as TKR, TCR and TSR owing to the problem of different track gauges (narrow/standard/broad gauge), it is important to develop the gauge-adjustable wheelset system to adapt easily to these gauges. Moreover, freight trains having the gauge-adjustable wheelsets should be passing various curved tracks in railroad networks. Therefore, to assure the safety of the gauge-adjustment whellset system, it is necessary to evaluate integrity of locking parts in the system using stress analysis. This study is focused on analyzing contact stress of locking parts by using FEA(finite element analysis) simulation during the gauge changeover operation and freight trains' service in the curved track, respectively.

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.

Running Monitoring by the Noise and Vibration Measurement near the Wheelset of the High-Speed Trains : A Preliminary Research (고속철도차량 윤축부근의 소음과 진동 측정을 통한 주행중 감시의 기초연구)

  • Lee, Jun-Seok;Choi, Sung-Hoon;Park, Choon-Soo
    • Proceedings of the KSR Conference
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    • pp.1454-1462
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    • 2008
  • This paper is focused on the analysis of the noise and vibration measured near the wheelset of the high-speed trains using a time-varying frequency transform as a preliminary research of running monitoring. Due to the non-stationary characteristics, it is necessary to examine noise and vibration of the train with time-varying frequency transforms. In this paper, the short-time Fourier transform method is utilized - the stored data is localized by modulating with a window function, and Fourier transform is taken to each localized data. For the examination, the non-stationary noise and vibration of the high-speed train's wheelset are measured by using some microphones and accelerometers, and those signals are stored in a on-board data acquisition system. The non-stationary random signal analyses with the short-time Fourier transform are performed, and the result are classified as follows; auto-spectral density, cross-spectral density, frequency response, and coherence functions. From those functions, it is possible to observe the frequency characteristics of sleepers, switchers, tunnels, and steel bridges. Also, some distinct peaks, which are not dependent upon the train's speed, are identified from the results.

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A Study on the Dynamic Behavior of Eddy Current Braking System for Korean High Speed Train (고속전철의 와전류 제동장치 동적 거동특성 연구)

  • 박찬경;최강윤;현승호;곽수태
    • Proceedings of the KSR Conference
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    • pp.147-154
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    • 2001
  • Dynamic behavior of high speed train is very important because the high speed train should be safe and satisfied with the ride comfort. An eddy current brake system is mounted on trailer bogie and wheelset. The eddy current braking force longitudinally exerts on the articulated trailer bogie and the attraction force vertically exerts on the wheelset. Because a frame of eddy current brake system is flexible, these forces generate the vertical vibration at middle point of the frame. Also, the vibration change the vertical clearance between an electromagnet and top of rail which affect the magnitude of braking and attracting forces. Therefore, the dynamic behavior of the eddy current braking system must be predicted for design the dynamic characteristic of its mounting system when normally operate on rail which have irregularity. Vampire program is used for Prediction of the dynamic behavior of an eddy current braking system.

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Evaluation of running safety for korean high speed railway vehicle (한국형 고속철도차량의 주행안전성 평가)

  • Ham Young-Sam;Hur Hyun-Moo
    • Proceedings of the KSR Conference
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    • pp.316-321
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    • 2003
  • The railroad is a means of large transportation which has many talents such as a safety and a regularity. That is a results from various confidential performance tests and evaluations of the system. The railroad system consist of various subsystems - vehicle, power supply, signal, communications, track structures, operations, etc. Among them, as an item of safety evaluation there is a measurement of wheel/rail force, so called a measurement of derailment coefficient. This is a very important item because a derailment of a train will bring about a big accident. Especially it is more important in high speed rail of which operation speed is over two times as fast as existing rail. In this paper, it is introduced to preprocess the wheelset for measuring wheel/rail force of high speed rail, such as to treat a measuring wheelset, adhesion of strain gauges and static load test, running test result of main line.

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Estimation of longitudinal velocity noise for rail wheelset adhesion and error level

  • Soomro, Zulfiqar Ali
    • Multiscale and Multiphysics Mechanics
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    • v.1 no.3
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    • pp.261-270
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    • 2016
  • The longitudinal velocity (forward speed) having significant importance in proper running of railway wheelset on track, depends greatly upon the adhesion ratio and creep analysis by implementation of suitable dynamic system on contamination. The wet track condition causes slip and slide of vehicle on railway tracking, whereas high speed may also increase slip and skidding to severe wear and deterioration of mechanical parts. The basic aim of this research is to design appropriate model aimed estimator that can be used to control railway vehicle forward velocity to avoid slip. For the filtration of disturbance procured during running of vehicle, the kalman filter is applied to estimate the actual signal on preferered samples of creep co-efficient for observing the applied attitude of noise. Thus error level is detected on higher and lower co-efficient of creep to analyze adhesion to avoid slip and sliding. The skidding is usually occurred due to higher forward speed owing to procured disturbance. This paper guides to minimize the noise and error based upon creep coefficient.

Fatigue Analysis of Locking Parts in the Gauge - Adjustable Wheel Set System in the Curved Track (곡선부 주행시 궤간 가변 잠금부품들의 피로해석)

  • Kim, Chul-Su;Ahn, Seung-Ho;Chung, Kwang-Woo;Jang, Seung-Ho;Kim, Jung-Kyu
    • Proceedings of the KSR Conference
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    • pp.1-6
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    • 2006
  • The gauge - adjustable wheelset system in the transcontinental railway represents a more effective way in comparison with other techniques for overcoming difference in track gauges. Moreover, freight trains having the gauge - adjustable wheelsets will be run various curved tracks of Eurasian railroad network such as TKT, TCR and TSR. Therefore, to assure the safety of the gauge - adjustable adjustment wheelset system, it is necessary to evaluate durability of locking parts in the system during freight trains' service in the curved track. In this study, it was performed to estimate fatigue life of locking parts under lateral wheel pressure by using durability simulator.

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Low Cycle Fatigue Characteristics of the Railway Wheels and Axles (차륜 및 차축 재료의 저주기 피로특성)

  • Kim D. J.;Seok C. S.;Seo J. W.
    • Proceedings of the KSR Conference
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    • pp.427-433
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    • 2005
  • Railway wheelset is the most essential part which undergoes severe cyclic loadings. In recent years, there has been increasing need for insuring the safety of running as the speed of the railway vehicles is getting higher. So it is required on the assessment of fatigue characteristics of the wheelset to consider plastic deformation which might be probable in the severe loading condition. In this study, total-strain controlled low cycle fatigue(LCF) test were performed to observe the LCF behaviors of the railway wheels and axles using companion specimens method. From the experimental results, the cyclic mechanical properties have been evaluated and total strain amplitude versus life relationship have been derived using the empirical Coffin-Manson law.

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