• Title, Summary, Keyword: Railway vehicle

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An Experimental Study on the Hybrid Composite Carbody Structure (하이브리드 복합재 철도차량 차체에 대한 시험적 연구)

  • Kim Jung-Seok;Jeong Jong-Cheol;Lee Sang-Jin
    • Composites Research
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    • v.18 no.6
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    • pp.19-25
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    • 2005
  • This paper has performed an experimental study on the hybrid composite carbody of Korean tilting railway vehicle. The hybrid composite carbody has the length of 23m and is comprised of a 40mm-thick aluminium honeycomb core and 2mm-thick woven fabric carbon/epoxy face sheet. In order to evaluate the structural behavior and safety of the hybrid composite carbody, the static load tests such as vertical load, end compressive load, torsional load and 3-point support load tests have been conducted. The test was performed under Japanese Industrial Standard (JIS) 17105 standard. from the tests, the maximum deflection was 12.3mm and the equivalent bending stiffness of the carbody was $0.81\times10^{14}\;kgf{\cdot}mm^2$. The maximum strain of the composite body was below $20\%$ of failure strain of the carbon/epoxy face sheet.

A Study on the Vibration Parameters for High Speed Face Milling Machining (고속 정면밀링가공을 위한 진동 파라미터에 관한 연구)

  • Jang, Sung-Min;Lee, Seung-Il
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.14 no.9
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    • pp.4149-4155
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    • 2013
  • High speed machining for higher cutting speed and feedrate lead to a increase of surface quality and material removal rate. This paper presents a study of the influence of cutting conditions on the vibration characteristics obtained by machining with face milling cutter for high speed machining. In this paper, Taguchi experimental design method which is based on orthogonal array table was applied to study vibration characteristics with high speed face milling cutter. The experimental conditions used orthogonal array of $L_{27}(3^{13})$. In this work, design and analysis of experiments is conducted to study the effects of these parameters on the vibration by using the S/N ratio, analysis of variance. Four cutting parameters namely, feed rate, champer length, cutting speed, and depth of cut were optimized with consideration of vibration characteristics.

VLC Based Positioning Scheme in Vehicle-to-Infra(V2I) Environment (차량-인프라간 가시광 통신 기반 측위 기술)

  • Kim, Byung Wook;Song, Deok-Weon;Lee, Ji-Hwan;Jung, Sung-Yoon
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.40 no.3
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    • pp.588-594
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    • 2015
  • Although GPS technology for location positioning system has been widely used, it is difficult to be used in intelligent transport systems, due to the large positioning error and limited area for receiving radio signals. Thanks to the rapid development of LED technology, LED lights become popular in many applications. Especially, visible light communications (VLC) has raised a lot of interests because of the simultaneous functioning of LED illumination and communication. Recent studies on positioning system using VLC mainly focused on indoor environments and still difficult to satisfy positioning accuracy and simple implementation simultaneously. In this paper, we propose a positioning system based on VLC using the coordinate information of LEDs installed on the road infrastructure. Extracting the LED signal, obtained through VLC, from the easily accessible camera image, it is possible to estimate the position of the car on the road. Simulation results show that the proposed scheme can achieve a high positioning accuracy of 1 m when large number of pixels is utilized and the distance from the LED light is close.

A Study on Priority Evaluation of the Rope-type Platform Safety Door(RPSD) Installation by Multi-criteria Decision Analysis (다기준 분석에 의한 로프형 승강장 안전도어의 설치 우선순위 산정에 관한 연구)

  • Jung, Byung Doo
    • Journal of The Korean Society of Civil Engineers
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    • v.35 no.3
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    • pp.639-645
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    • 2015
  • Recently, a study on the commercialization of Rope type Platform Safe Door (RPSD) technology has commenced. The study focuses on RPSD, in which a rope screen ascends to allow safe passage from the platform to the transit vehicle in aboveground stations. Currently, a pilot installation has taken in place with Daegu Metro Line 2 in MoonYang station starting from March of 2013. However, there is a need to select an appropriate pilot installation's object for the improvement in the future RPSD. An appropriate designation would correspond with the needs of the railroad corporation and as a historic railway platform with safe facilities. This study tried to usa Analytic Hierarchy Process (AHP) to determine the priority of the KTX stations to attain a list of appropriate designations for future RPSD installations by analyzing the followings: management of the facilities, operational risks, and intent of business projects. As a case study, it was applied to the evaluation of the KTX stations. For the application, it used relative measurement to calculate the weight of upper level structuring, and absolute measurement for low level structuring instead of pairwise comparisons.

A Study on Cost Optimization of Preventive Maintenance for the Second Driving Devices for Korea Train Express (KTX 2차 구동장치에 대한 예방정비 비용의 최적화에 관한 연구)

  • Jung, Jin-Tae;Kim, Chul-Su
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.17 no.2
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    • pp.1-7
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    • 2016
  • Although the second driving device of KTX, which consists of the wheel and the axle reduction gears unit, is a mechanically integrated structure, its preventive maintenance (PM) requires two separate intervals due to the different technical requirements. In particular, these subsystems perform attaching and detaching work simultaneously according to the maintenance directive. Therefore, to reduce the unnecessary amount of PM and high logistic availability of the train, it is important to optimize PM with regard to reliability-centered maintenance toward a cost-effective solution. In this study, fault tree analysis and reliability of the subsystems, considering the criticality of the components, were performed using the data derived from field data in maintenance. The cost optimization of the PM was derived from a genetic algorithm considering the target reliability and improvement factor. The cost optimization was derived from a maximum of the fitness function of the individual in generation. The optimal TBO of them using the genetic algorithm was 2.85x106 km, which is reduced to approximately 21% compared to the conventional method.

A Study on Train Braking Performance Assessment Methods Using Braked Weight Percentage (제동중량비율을 이용한 도시철도차량 제동성능 평가방법 연구)

  • Choi, Don-Bum;Lee, Kang-Mi;Yoon, Yong-Ki
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.17 no.11
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    • pp.545-551
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    • 2016
  • In this study, we evaluate the braking performance of an urban railway vehicle to verify its basic safety condition. The braking performance evaluation methods, deceleration measurement and braked weight percentage, were compared for trains with different numbers of cars, in order to assess the advantages of each method and their compatibility. With a probabilistic braking model, the effect of the adhesion coefficient distribution was analyzed in accordance with the train composition. A train with many cars has a narrower deceleration distribution width than one with few cars. The braked weight percentage method is expected to be useful in the design of train signal systems, because it allows the braking distance to be calculated for various initial brake velocities. The deceleration distribution model and its results are expected to be useful as a basis for precise train signal design.

A Study on an Impedance Matching Technique for Rail Power Line Communication (레일 전력선통신을 위한 임피던스 정합방안 연구)

  • Seo, Ill-Kwon;Ahn, Seung-Ho;Kim, Chul-Su
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.17 no.11
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    • pp.202-207
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    • 2016
  • An auxiliary real-time train communications system among drivers, train-traffic controllers and field workers is necessary to share hazard information (i.e. rockfall detection, track maintenance) in low visibility zones (long tunnels and steep curved track). To develop the appropriate communication system, this paper proposes a new way of power line communication using the rail track (Rail - PLC), which has little noise and distortion of attenuation. Therefore, it is important to measure the impedance of the rail and to apply an impedance matching technique to increase the transmission characteristic of the Rail - PLC. This study would evaluate the reflection and the transmission characteristics of the rail using a network analyzer and an impedance matching transformer. The suitable impedance matching ratio was 1:3.28 from the result of back-to-back testing. The results confirmed that the transformer can improve the performance of the transmission signal in Rail - PLC using an impedance matching technique.

Sound-Insulation Design of Aluminum Extruded Panel in Next-Generation High-Speed Train (차세대 고속철도 차량용 알루미늄 압출재의 차음 설계)

  • Kim, Seock-Hyun;Seo, Tae-Gun;Kim, Jeong-Tae;Song, Dal-Ho
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.35 no.5
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    • pp.567-574
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    • 2011
  • Aluminum extruded panels are widely used instead of corrugated steel panels for weight reduction in high-speed trains. Of the layers in the train body, it makes the largest contribution to the sound insulation. However, compared with that of a flat panel with the same weight, the TL of the aluminum extruded panel is remarkably lower in the local resonance frequency band. We study aluminum extruded panels for next-generation 400-km/h trains. We investigate the problem of sound insulation and propose a practical method to improve the sound-insulation performance. The local resonance frequency region is increased by a modification of the core structure, and urethane foam is placed in the core. The effect on the sound insulation is verified by experiments. Finally, the improvement for the entire sound-transmission loss is estimated for the layered floor panels of express trains.

A Study on the Intercity Mode Choice Behavior of Daegu Citizens According to the Introduction of Gyeongbu High-Speed Railway (경부 고속철도 개통에 따른 대구시민의 지역 간 통행수단 선택행태 분석에 관한 연구)

  • Yun, Dae-Sik;Yuk, Tae-Suk;Kim, Sang-Hwang
    • Journal of Korean Society of Transportation
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    • v.24 no.1
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    • pp.29-38
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    • 2006
  • After the first opening of the KTX in April 2004, travel time between major cities has been dramatically reduced. The reduction rates range from 32% to 47%. Considering travel time reduction between major cities, this study concerned about the intercity travel impact of the KTX operation. This study aimed to analyze intercity mode choice behavior of Daegu Citizens according to the first opening of the KTX. This study takes place in two sections. These are (i) the section of KTX between Daegu and Seoul, and (ii) the section of KTX between Daegu and Daejeon. This study estimated empirical models for analyzing intercity mode choice behavior according to the first opening of the KTX. This study makes use of the data from travel survey from Daegu metropolitan area. The main part of the survey was carried out in the KTX Dong-Daegu station. The survey data includes the information on travel from Daegu to Daejeon and from Daegu to Seoul. In order to analyze intercity choice behavior according to the frist opening of the KTX, multinomial model structure is used. For the model specification, a variety of behavioral assumptions about the factors which affect the mode choice, were considered. From the empirical model estimation, it is found that OVTT(Out-of-Vehicle Travel Time), OVTC(Out-of-Vehicle Travel Cost), IVTT(In-Vehicle Travel Time), IVTC(In-Vehicle Travel Cost), travel frequency, travel purpose, sex, age, occupation. household income, individual income are significant in choosing intercity travel mode. However, it is found that the intercity nde choice behavior is different between (i) the section of KTX between Daegu and Seoul, and (ii) the section of KTX between Daegu and Daejeon. Furthermore, some policy implications are discussed in conclusion.

Analytical Study of Railroad Bridge for Maglev Propulsion Train with Dynamical Influence Variable (동적영향변수를 통한 자기부상열차용 철도교의 해석적 연구)

  • Yoo, Yi-Seul;Park, Won-Chan;Yhim, Sung-Soon
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.19 no.4
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    • pp.532-542
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    • 2018
  • Because maglev trains have a propulsion and absorption force without contact with the rails, they can drive safely at high-speed with little oscillation. Recently, test model of a maglev propulsion train was produced and operated, and has since been chosen as a national growth industry in South Korea; there have been many studies and considerable investment in these fields. This study examined the dynamic responses due to bridge-maglev train interaction and basic material to design bridges for maglev trains travelling at high-speed. Depending on the major factors affecting the dynamic effects, the scope of this study was restricted to the relationship between dynamic responses. A concrete box girder was chosen as a bridge model and injured train and rail types in domestic production were selected as the moving train load and guideway analysis model, respectively. From the analysis results, the natural frequency of a bridge for a maglev train, which has a deflection limit L/2000, was higher than those of bridges for general trains. The dynamic responses of the girder of the bridge for a maglev train showed a substantial increase in proportion to the velocities of the moving train like other general bridge cases. Maximum dynamic response of the girder is shown at a moving velocity of 240km/h and increased with increasing moving velocity of train. These results can be used to design a bridge for maglev propulsion trains and provide the basic data to confirm the validity and verification of the design code.