• Title/Summary/Keyword: Wheelset

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Collision-induced Derailment Analysis of a Finite Element Model of Rolling Stock Applying Rolling Contacts for Wheel-rail Interaction (차륜-레일 구름접촉을 적용한 철도차량 유한요소 모델의 충돌 기인 탈선거동 해석)

  • Lee, Junho;Koo, Jeongseo
    • Transactions of the Korean Society of Automotive Engineers
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    • v.21 no.3
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    • pp.1-14
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    • 2013
  • In this paper, a finite element analysis technique of rolling stock models for collision-induced derailments was suggested using rolling contacts for wheel-rail interaction. The collision-induced derailments of rolling stock can be categorized into two patterns of wheel-climb and wheel-lift according to the friction direction between wheel flange and rail. The wheel-climb derailment types are classified as Climb-up, Climb/roll-over and Roll-over-C types, and the wheel-lift derailment types as Slip-up, Slip/roll-over and Roll-over-L types. To verify the rolling contact simulations for wheel-rail interaction, dynamic simulations of a single wheelset using Recurdyn of Functionbay and Ls-Dyna of LSTC were performed and compared for the 6-typical derailments. The collision-induced derailment simulation of the finite element model of KHST (Korean High Speed Train) was conducted and verified using the theoretical predictions of a simplified wheel-set model proposed for each derailment type.

Wheelset Steering Control for Improvement a Running Safety on Curved Track (곡선부 주행안전성 향상을 위한 윤축 조향 제어)

  • Hur, Hyun Moo;Ahn, Da Hoon;Kim, Nam Po;Sim, Kyung Seok;Park, Tae Won
    • Journal of the Korean Society for Precision Engineering
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    • v.31 no.9
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    • pp.759-764
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    • 2014
  • Lateral force of wheel is important parameter when we evaluate the safety of a railway vehicle on curved track. The lateral force of wheel is influenced by the steering performance of wheelsets. Generally, in passive type vehicles, the steering performance of wheelsets is influenced by the parameters like primary spring stiffness, wheel base, conicity of the wheel profile, etc. But, the steering performance of passive type vehicle has its limit. To overcome the limit of the steering performance of passive type vehicle, active steering technology is being developed. In this paper, we analyze the lateral force of wheel and the safety of the railway vehicle on curved track by adopting the active steering technology. As results of dynamic analysis for vehicle model equipped with active steering system, the lateral force of wheel is reduced and the safety is improved remarkably.

Fracture Mechanics Characteristics of Wheel and Axle For High Speed Train (고속철도용 차륜과 차축의 파괴역학적 특성)

  • Kwon, Seok-Jin;Seo, Jung-Won;Lee, Dong-Hyung;Ham, Young-Sam
    • Journal of the Korean Society for Precision Engineering
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    • v.27 no.8
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    • pp.28-34
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    • 2010
  • Railway wheel and axle is the most critical components in railway system. A wheel and axle failure can cause a derailment with its attendant loss of life and property. The service conditions of railway vehicles have become severe in recent years due to a general increase in operating speeds. Therefore, more precise evaluate of wheelset strength and safety has been desired. Fracture mechanics characteristics such as dynamic fracture toughness, fatigue threshold and charpy impact energy with respect to the tread, plate, disc hole of wheel and the surface of press fitted axle are evaluated. This paper describes the difference of fracture toughness, fatigue crack growth and fatigue threshold at the locations of wheel and axle. The results show that the dynamic fracture toughness, $K_{ID}$, is obviously lower than static fracture toughness, $K_{IC}$ and the fracture mechanics characteristics are difference to the location of wheel tread and hole.

Dynamic response of railway bridges traversed simultaneously by opposing moving trains

  • Rezvani, Mohammad Ali;Vesali, Farzad;Eghbali, Atefeh
    • Structural Engineering and Mechanics
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    • v.46 no.5
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    • pp.713-734
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    • 2013
  • Bridges are vital components of the railroads. High speed of travel, the periodic and oscillatory nature of the loads and the comparable vehicle bridge weight ratio distinguish the railway bridges from the road bridges. The close proximity between estimations by some numerical methods and the measured data for the bridge-vehicle dynamic response under the moving load conditions has boosted the confidence in the numerical analyses. However, there is hardly any report regarding the responses of the railway bridges under the effect of the trains entering from the opposite directions while running at unequal speed and having dissimilar geometries. It is the purpose of this article to present an analytical method for the dynamic analysis of the railway bridges under the influence of two opposing series of moving loads. The bridge structural damping and many modes of vibrations are included. The concept of modal superposition is used to solve for the system motion equations. The method of solution is indeed a computer assisted analytical solution. It solves for the system motion equations and gives output in terms of the bridge deflection. Some case studies are also considered for the validation of the proposed method. Furthermore, the effects of varying some parameters such as the distance between the bogies, and the bogie wheelset distance are studied. Also, the conditions of resonance and cancellation in the dynamic response for a variety of vehicle-bridge specifications are investigated.

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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    • 2008.11a
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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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Infrared Thermographic Monitoring for Failure Characterization in Railway Axle Materials (철도차량 차축 재료의 파괴특성 적외선열화상 모니터링)

  • Kim, Jeong-Guk
    • Journal of the Korean Society for Nondestructive Testing
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    • v.30 no.2
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    • pp.116-120
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    • 2010
  • The wheelset, an assembly of wheel and axle, is one of important parts in railway bogie, directly related with the running safety of railway rolling stock. In this investigation, the tensile failure behavior of railway axle materials was investigated. The tensile coupons were prepared from the actual rolling stock parts, which were operated over 20 years. The tensile testing was performed according to the KS guideline. During tensile testing, an infrared camera was employed to monitor temperature changes in specimen as well as demonstrate temperature contour in terms of infrared thermographic images. The thermographic images of tensile specimens showed comparable results with mechanical behavior of tensile materials. In this paper, the failure mode and behavior of railway axle materials were provided with the aid of infrared thermography technique.

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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Study on 3-D Simulation for Overriding Evaluation of Urban Train (도시철도차량 타고오름 평가를 위한 3 차원 충돌시뮬레이션 기법 연구)

  • Jin, Sung Zu;Jung, Hyun Seung;Kwon, Tae Soo;Kim, Jin Sung
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.39 no.10
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    • pp.1063-1068
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    • 2015
  • In this paper, we propose a collision simulation technique the evaluation of urban trains. We perform simulation that include a dynamics bogie model which represents the dynamic behavior of bogies and a finite-element model that can model crash behavior. We perform simulation in accordance with the 40-mm vertical offset head-on scenario for overriding the evaluation of the EU and domestic crashworthiness regulations. We evaluate the overriding by the vertical displacement of the wheelset using the overriding evaluation standard. Finally, if proposed simulation technique is applied, we can evaluate the overriding for urban-train crashworthiness regulations.

An Experimental Study of Squeal Noise Characteristics for Railway Using a Scale Model Test Rig (축소 모델 실험장치를 이용한 철도 스킬소음의 특성에 대한 실험적 연구)

  • Kim, Jiyong;Hwang, Donghyeon;Lee, Junheon;Kim, Kwanju;Kim, Jaechul
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.25 no.5
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    • pp.352-360
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    • 2015
  • Squeal noise is a harsh, high-pitched sound that occurs when railways are running at sharp curve tracks. The cause of squeal noise is known to be the transient lateral traction force between wheel and rail. Field measurements are too difficult to control the parameters. Thus, the scaled test rig should have been made in order to investigate the generating mechanism of squeal noise. The unique feature of our test rig, HSTR(Hongik Squeal Testing Rig), is that DOFs of its wheelset are as close to as those of the real railway. The attack angle and running speed of the rail roller are controlled in real time for simulating a transient characteristic of driving curve. The environment conditions, such as given axle load, running speed, and wheel's yaw angle have been identified for generating squeal noise and the squeal noise itself has been measured. The relation between wheel creepage and creep force in lateral direction and the criteria for squeal noise have been investigated, which results has been verified by finite element method.