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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of the Korean Society for Railway
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Journal DOI :
Korean Society for Railway
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Volume & Issues
Volume 17, Issue 6 - Dec 2014
Volume 17, Issue 5 - Oct 2014
Volume 17, Issue 4 - Aug 2014
Volume 17, Issue 3 - Jun 2014
Volume 17, Issue 2 - Apr 2014
Volume 17, Issue 1 - Feb 2014
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Vibration Analysis of a Bogie Using Linearized Dynamic Equations of a Multibody System
Kang, Juseok ;
Journal of the Korean Society for Railway, volume 17, issue 5, 2014, Pages 321~327
DOI : 10.7782/JKSR.2014.17.5.321
In this paper, linear dynamic equations are derived from nonlinear dynamic equations of constrained multibody systems using the QR decomposition method. The derived linear equations are applied to a railway vehicle bogie. The vibration characteristics of the railway vehicle are investigated by calculating the natural mode and transfer function of the bogie frame in relation to rail-roughness input. The main modes of the bogie were found below 35Hz, and the local modes above 198Hz. The magnitude of the vertical transfer function varied with the forward velocity due to vertical and pitch modes, which were influenced by the forward velocity. The magnitude of the lateral transfer function was negligibly small, and the mode in the longitudinal direction was excited for longitudinal transfer function regardless of the forward velocity.
Analysis of Cooling Air Current and Efficiency of Air Conditioning in the Underground Subway Station with Screen-Door Opening and Closing
Jang, Yong-Jun ; Ryu, Ji-Min ; Jung, Ho-Sung ;
Journal of the Korean Society for Railway, volume 17, issue 5, 2014, Pages 328~335
DOI : 10.7782/JKSR.2014.17.5.328
Numerical prediction methods were applied to investigate the turbulent air currents and air-conditioning efficiency in an underground subway station, and the results compared to experimental data. The Shin-gumho Station(
floor underground and 43.6m in depth) in Seoul was selected for the analysis. The entire station was covered for simulation and the ventilation mode was ordinary. The ventilation diffusers were modeled as 95 square shapes of
in the lobby and as 222 square shapes in the platform. Cooling air of
was supplied and the returned air of
is exhausted in the lobby and the cooling air of
is supplied and the returned air of
was exhausted in the platform which is the same as the experimental data. The cases of the screen-door-closed and open were respectively investigated. A total of 7.5million grids were generated and the whole domain divided into 22 blocks for MPI efficiency of calculation. Large eddy simulation (LES) was applied to solve the momentum and energy equation.
Torque Distribution Algorithm of Independent Drive Articulated Vehicle for Small Radius Turning Performance
Lee, Kibeom ; Hwang, Karam ; Tak, Junyoung ; Suh, In-Soo ;
Journal of the Korean Society for Railway, volume 17, issue 5, 2014, Pages 336~341
DOI : 10.7782/JKSR.2014.17.5.336
The articulated structures seen in train or tram applications are being applied in road transportation systems, for use in mass passenger transit. When articulated vehicles are driven on public roads, they no longer follow a guided track. Therefore, there are a lot of control elements that need to be considered, such as turning radius, swept path width, off-tracking, and swing-out. Some of the currently available articulated vehicles on roads are equipped with an independent drive system; a system that has one motor at each wheel. Through this drive system, each wheel can be independently controlled, making precise and quick dynamic stability control possible. In this paper, we propose a torque distribution algorithm that can reduce the overall turning radius of the articulated vehicle, which has been verified through dynamic simulation.
Analysis of the Critical Speed and Hunting Phenomenon of a High Speed Train
Song, Ki-Seok ; Koo, Ja-Choon ; Choi, Yeon-Sun ;
Journal of the Korean Society for Railway, volume 17, issue 5, 2014, Pages 342~348
DOI : 10.7782/JKSR.2014.17.5.342
Contact between wheel and rail leads to the creep phenomenon. Linear creep theory, assuming linear increase in the creep force vs creep, results in a critical speed at which the vibration of a railway vehicle goes to infinity. However, the actual creep force converges to a limited value, so that the vibration of a railway vehicle cannot increase indefinitely. In this study, the dynamics of a railway vehicle is investigated with a 6 DOF bogie model includingthe nonlinear creep curves of Vermeulen, Polach, and a newly calculated creep curve with strip theory. Strip theory considers the profiles of the wheel and rail. The results show that the vibration of a railway vehicle results in a limit-cycle over a specific running speed, and this limit-cycle becomes smaller as the slope of the creep-curve steepens. Moreover, a hunting phenomenon is caused due to flange contact, which restricts the magnitude of the limit-cycle.
A Study on the Design of Onboard Speed Profile of the ETCS-L2 System
Lee, Jong-Seong ; Jeon, Jae-Hun ; Jung, Gyung-Jang ; Kang, Deok-Won ;
Journal of the Korean Society for Railway, volume 17, issue 5, 2014, Pages 349~354
DOI : 10.7782/JKSR.2014.17.5.349
Other foreign countries already apply ETCS LEVEL 2 in signaling systems. It provides added functions to control a train using wireless communication compared with ETCS LEVEL 1. Nowadays, the ETCS LEVEL 2 system is being applied on revenue services more and more frequently. Therefore, it is necessary to develop ETCS LEVEL 2 to apply in this country. The advanced technology of the ETCS LEVEL 2 system provides continuous control for train protection, and ATP function, by comparing discontinuous controls on ETCS LEVEL 1. ETCS LEVEL 2 is a better system model for improving passenger safety. This paper describes the design of an onboard speed profile for the ETCS LEVEL 2 system and it forecasts the future of ETCS.
Effects of Transverse Cracks on Stress Distributions of Continuously Reinforced Concrete Tracks Subjected to Train Loads
Bae, Sung Geun ; Choi, Seongcheol ; Jang, Seung Yup ; Cha, Soo Won ;
Journal of the Korean Society for Railway, volume 17, issue 5, 2014, Pages 355~364
DOI : 10.7782/JKSR.2014.17.5.355
The restrained volume changes of concrete due to variations of temperature and moisture produce transverse cracks in continuously reinforced concrete tracks (CRCTs). Such cracks are known to significantly affect the behaviors and long-term performance of CRCT. To investigate the effects of the transverse cracks on the behavior of CRCT and to develop more reasonable maintenance standards for cracks, in this study, the stress distribution of the track concrete layers (TCL) and the hydraulically stabilized base course (HSB) with transverse cracks were numerically predicted by a three dimensional finite element analysis when CRCT was subjected to train loads. The results indicate that the bending stresses of TCL and vertical stresses at the interfaces between TCL and HSB increased as the cracks were deepened. In addition, vertical stresses were locally concentrated near reinforcing steel in cracks in TCL when full-depth cracks developed, which may lead to punch-outs in CRCTs. Comparably, the effects of crack width and spacing were not as significant as crack depth. This study indicates that ensuring the long-term performance of CRCTs requires adequate maintenance not only for crack width and spacing but also for crack depth. Our results also show that locating HSB joints between sleepers is beneficial to the long-term performance of CRCTs.
Early Strength Development of Concrete Cured with Microwave Heating Form
Koh, Tae Hoon ; Hwang, Seon Keun ; Moon, Do Young ; Yoo, Jung Hoon ; Song, Jin Woo ; Ko, Ji Soo ;
Journal of the Korean Society for Railway, volume 17, issue 5, 2014, Pages 365~372
DOI : 10.7782/JKSR.2014.17.5.365
Technologies for rapid concrete curing using elevated temperature are important for saving cost and time when constricting concrete structures. Recently, a microwave heating form was developed. In this study the early strength of concrete cured by the developed form was experimentally investigated. Large scale mock up tests were conducted six times, and the results were analyzed based on the maturity theory. Logarithmic correlation curves were generated based on the measured strength and estimated maturity. It was confirmed that the strength development of the concrete cured by microwave heating form can be estimated by the equivalent age theory usually applied to steam-curing technology. By using the microwave heating form, one day at most is enough to get the required strength for the safe removal of forms, even in cold weather.
Economic Analysis on Transshipment and the Gauge-Adjustable System for Trans-Continental Container Transportation
Chung, Kwang Woo ;
Journal of the Korean Society for Railway, volume 17, issue 5, 2014, Pages 373~380
DOI : 10.7782/JKSR.2014.17.5.373
With a view to the commercialization of the Korean automatic variable-gauge bogie in the Eurasia railway system, the aim of this research was to perform an economic analysis concerning the possible introduction and operation of this bogie at the present time. For this purpose, we compared the possible types of freight connection service for container transportation, transshipment and the gauge-adjustable system, estimating the total life-cycle cost (LCC) incurred by each system, depending on type and quantity, over the whole process of acquisition, operation, maintenance and disposal. Based on this, we presented a case-by case analysis. Furthermore, in estimating economic feasibility, we analyzed the cost-benefit ratio taking into account not only the objective LCC, but also the reduced time required for the gauge-change and customer convenience. After estimating the LCC and analyzing the cost-benefit ratio of the respective systems, we demonstrated the economic superiority of view of the gauge adjustable system.
Study on the Local Factors Affecting Availability of Car-Sharing in Seoul
Choi, Hyunsu ; Park, Juntae ;
Journal of the Korean Society for Railway, volume 17, issue 5, 2014, Pages 381~389
DOI : 10.7782/JKSR.2014.17.5.381
This research focuses on the current trend of `Sharing Transportation` to clarify the regional factors having a decisive effect on the use of Car Sharing. To accomplish this, the current research is built a Database of the regional characteristics of Car Sharing spots based on railway stations in Seoul and performed an analysis of the primary regional factors affecting Car Sharing usage. As a result, we found conclusive factors affecting the use of Car Sharing. This research can be utilized for establishing strategies and effective measures to support the use of Car Sharing and sustainable development with respect to issues of motorization.