• Title/Summary/Keyword: 윤중감소율

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A Study on the Assessment of Running Safety of Railway Vehicle passing through Curve (곡선부 통과 열차의 주행안전성 평가에 관한 연구)

  • Park, Kwang-Soo;Lee, Hi-Sung
    • Journal of the Korean Society for Railway
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    • v.10 no.5
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    • pp.492-498
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    • 2007
  • For the running safety assessment of Saemaul train passing through curves, an analysis model for multibody system has been developed. By using this model and ADAMS/Rail, sensitivity analyses depending on the variation of parameters related to the derailment coefficients have been conducted. At low speed, the derailment coefficient and the unload ratio of right wheel showed higher than left wheel, while those of left wheel showed higher than right wheel at high speed. According to decrease of curve radius, the derailment coefficient and the unload ratio were increased. When the length of transition curve was increased, the derailment coefficient was increased but there was no change on the unload ratio. According to the increase of cant, the derailment coefficient and the unload rate were increased.

Wheel Off-loading test procedure and result (단차 상태 차량 윤중 감소율 시험 절차 및 결과)

  • 김진태;이원상
    • Proceedings of the KSR Conference
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    • pp.857-862
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    • 2002
  • The bogie, when run on the twist track develops the wheel off-loading factor. This will be comfirmed by testing under different loading conditions and air springs inflated and deflated in all conditions. Under the most extreme twist track condition, EMU (Electrical Multiple Unit) shall not over the wheel off-loading requirement 60% defined on UIC / ORE report. This paper describes the wheel off-loading test procedure according to UIC / ORE and test result of DMRC EMU of INDIA carried out to find out to meet the requirement defined in UIC / ORE.

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Determination of the Upper Limit of Railpad Stiffness in Concrete Track of High-Speed Railways Considering the Running Stability of Train (주행안정성을 고려한 고속철도 콘크리트궤도 레일패드강성 상한값 결정)

  • Yang, Sin-Chu;Jang, Seung-Yup;Kim, Eun
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • pp.485-488
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    • 2011
  • 본 연구에서는 경부고속철도의 콘크리트궤도에서 열차주행안전측면에서 관리해야할 레일패드강성의 상한값을 차량 및 궤도의 동특성과 운영환경을 고려하여 결정하는 방법을 제시하였다. 차량과궤도의 상호작용의 해석의 중요 입력파라메타인 궤도틀림과 관련하여 프랑스 및 독일에서 제시한 궤도틀림 PSD(Power Spectral Density)와 경부 1단계구간 콘크리트궤도에서 계측한 궤도틀림 자료를 통하여 얻은 PSD를 기초로 하여 넓은 범위의 주파수영역에서 적용할 수 있는 콘크리트궤도의 궤도틀림 PSD를 제시하였다. 제시된 PSD 기준모델을 사용하여 시간영역에서의 궤도틀림 입력을 Random Generation을 통하여 구한 후 개발된 차량-궤도 상호작용해석 기법을 사용하여 레일패드에 따른 윤중감소율을 산정하였다. 산정된 윤중감소율에 대하여 국내 철도차량 안전기준에 관한 규칙의 탈선계수 규정을 적용하여 주행안전측면에서 허용할 수 있는 레일패드강성의 상한값을 제시하였다.

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Study of Influence of Wheel Unloading on Derailment Coefficient of Rolling Stock (철도차량의 윤중 감소가 탈선계수에 미치는 영향 연구)

  • Koo, Jeong Seo;Oh, Hyun Suk
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.37 no.2
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    • pp.177-185
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    • 2013
  • A new theoretical derailment coefficient model of wheel-climb derailment is proposed to consider the influence of wheel unloading. The derailment coefficient model is based on the theoretical derailment model of a wheelset that was developed to predict the derailment induced by train collisions. Presently, in domestic derailment regulations, a derailment coefficient of 0.8 is allowable using Nadal's formula, which is for a flange angle of $60^{\circ}$ and a friction coefficient of 0.3. However, theoretical studies focusing on different flange angles to justify the derailment coefficient of 0.8 have not been conducted. Therefore, this study theoretically explains a derailment coefficient of 0.8 using the proposed derailment coefficient model. Furthermore, wheel unloading of up to 50% is accepted without a clear basis. Accordingly, the correlation between a wheel unloading of 50% and a derailment coefficient of 0.8 is confirmed by using the proposed derailment coefficient model. Finally, the validity of the proposed derailment coefficient model is demonstrated through dynamic simulations.

Evaluation of Curving Performance and Running Safety of New High-Power Electric Locomotive (신형 고출력 전기기관차의 곡선추종성 및 주행안전성 평가)

  • Ham, Young Sam
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.37 no.6
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    • pp.827-832
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    • 2013
  • In this study, curve responsiveness was assessed based on the lateral force and running safety was evaluated based on the wheel unloading ratio and derailment coefficient, which is the ratio of the wheel load and the lateral force. The evaluation of the curving performance and running safety of the new high-power electric locomotive showed that the derailment coefficient appeared higher when the wheel-set was set to the front of the train instead of being placed backward, and the maximum value of the derailment coefficient was recorded as 0.572 on the Gyeongbu line. Furthermore, the lateral force increased in curved sections, and it appeared to be proportional to the curve radius. Meanwhile, a maximum axis lateral force of 77.6 kN was recorded on the Taebaek line, and the wheel unloading ratio was 47.6% on the Yeongdong line. Finally, the running safety at the maximum speed as well as the through-curve performance of the curve radius satisfied the required standards.

Evaluation of Train Running Safety During Construction of Temporary Bridge on Existing Railway (기존선에서 가설교량 시공에 따른 열차의 주행안전성 평가)

  • Eum, Ki-Young;Bae, Jae-Hyoung;Choi, Chan-Yong
    • Journal of the Korean Society for Railway
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    • v.14 no.3
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    • pp.234-239
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    • 2011
  • Installing the temporary bridge after excavating the railway requires installing movable cross beam, but as it doesn't requires isolating the catenary or cutting the rail, it's applicable to double-track with frequent operation. In this study, a displacement meter was placed on temporary bridge to monitor the displacement pattern in curve section (R400) completed using temporary bridge method, and wheel load, lateral pressure and derailment coefficient were measured to evaluate the load imposed on track and the stability in curve section (R400) for quantitative evaluation of training running safety. As a result of the measurement, when trains passing over a temporary bridge, the maximum value of Wheel load and Lateral Force is analyzed as the 51% and 81% of standard level according to foreign country's performance tests, There is no trouble with stability analysis in Wheel load and Lateral Force occurring. Additionally, Wheel load and Lateral Force considered as the safety standard are tested 49% of limiting value regardless of trains, which the norm value quite well, there is no problem with train running.

An Analysis of Running Safety for Railway Vehicle Depending on Actual Track Conditions (실제선로 조건에 따른 철도차량의 주행안전성 해석)

  • Kim, Yong-Won;Lee, Hi-Sung
    • Journal of the Korean Society for Railway
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    • v.12 no.6
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    • pp.983-988
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    • 2009
  • When the railway vehicle passing through curves & transitions, the running speed must improve by proposing the practical standard about maximum running possibility speed of each section on existing line considering running safety. In this paper, when the railway vehicle passing through curves of actual track conditions (Namsunghyun-Chungdo up & down lines), the effect that has influence on running safety is examined to devise the high speed of vehicle which passing through curves which risk of derailment is high. The running safety analysis is performed that running speed by curve radius improves 5-20% compared with existing speed under actual track conditions. In result of the running safety analysis, in case the speed condition is fewer than 15% compared with existing speed, the derailment coefficient and unloading ratio are within acceptable level. so we could confirm possibility of speed improvement on the whole Namsunghyun-Chungdo up & down lines.

A Study on the Running Stability of the High-speed Train by Wind Pressure and Crossing (고속열차의 풍압 및 교행에 의한 주행안정성 연구)

  • Jeon, Chang-Sung;Yun, Su-Hwan;Kim, Seog-Won
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.21 no.12
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    • pp.880-887
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    • 2020
  • This study was conducted to investigate the running stability of a high-speed train operated in a tunnel and an open field when external forces such as wind pressure and train crossings were applied to the vehicle. With no external force, the running stability at 400 km/h was examined, and the wheel weight reduction ratio, lateral pressure of the axles, and derailment coefficient satisfied the criteria of the technical standards for a high-speed train. When the distance between the centers of the tracks is 4.6 m, the external force caused by train crossing slightly affects the lateral acceleration of the vehicle but does not significantly affect the wheel weight reduction rate, lateral pressure, and derailment coefficient in a tunnel and open filed. When the distance is 4.6~5.0 m, the wheel weight reduction ratio, lateral pressure, and derailment coefficient satisfy the criteria with 20 m/s wind. When the wind speed was 30 m/s, the derailment coefficient satisfied the criteria, and the other variables exceeded them. It is predicted that a high-speed train can be operated safely at 400 km/h with wind speed of up to 20 m/s, and it should be slowed down at a wind speed of 30 m/s.

Evaluation of Running Safety for Depressed Center Flat Car of 3-axle Bogie (3-축 대차 곡형평판차량의 주행안전성 평가)

  • Ham, Young-Sam;Seo, Jung-Won;Kwon, Seok-Jin;Lee, Dong-Hyung
    • Journal of the Korean Society for Precision Engineering
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    • v.28 no.5
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    • pp.559-564
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    • 2011
  • 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, main line running test on the basis of the derailment theory and experience. It is executed main line test into more than 90km/h for estimating the curving performance and running safety of depressed center flat car of 3-axle bogie. As the test results, could confirm the curving performance and running safety of depressed center fiat car of 3-axle bogie from the results of the wheel unloading, lateral force, derailment coefficient etc. Derailment coefficient was less than 0.6, and lateral force allowance limit and wheel load reduction ratio were enough safe.

Running Safety of a Long Span Suspension Bridge under the Passage of a High Speed Train (장경간 현수교의 고속열차 주행 시 운행한계기준 검토)

  • Kim, Sung-Il;Kim, Hyun-Min
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • pp.477-480
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    • 2011
  • 장경간 케이블 교량은 과도한 변위 발생 등의 이유로 엄격한 안전성 및 사용성이 요구되는 철도교량에서는 제한적으로 적용되고 있다. 즉, 철도교량으로서 요구되는 주행안전성과 승차감을 만족하기 위해서는 면밀한 분석이 필요하다. 본 연구에서는 교량/열차 상호작용 해석을 수행하여 열차에서의 응답을 통해 교량 상을 주행하는 열차의 주행안전성 및 승차감을 직접적으로 평가하고자 하였다. 즉, 중앙경간 300m의 현수교를 주행하는 KTX 열차에 대하여 열차 내부의 가속도와 윤중감소율을 구해 평가하는 방법을 취하였다. 또한, 이동 열차하중과 지진하중이 동시에 작용할 경우를 고려한 교량/열차/지진 상호작용해석을 수행하여 지진 시의 응답을 평가하였다.

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