• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.22-23
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• 2015

As wireless power transfer (WPT) technology using strongly coupled electromagnetic resonators is a recently explored technique to realize the large power delivery and storage without any cable or wire, this technique is required for diffusion of electric vehicles (EVs) since it makes possible a convenient charging system. Typically, since the normal conducting coils are used as a transmitting coil in the CPT system, there is limited to deliver the large power promptly in the contactless EV charging system. From this reason, we proposed the combination CPT technology with HTS transmitting antenna, In this study, we examined the improvement of transmission efficiency and properties for HTS and copper antennas, respectively, at 30 cm distance. Thus, we obtained improved transfer efficiency with HTS antenna over 10% compared with copper antenna

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.1024-1031
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• 2008

The performance of magnetic levitation controller is affected from not only levitation control algorithm but also the interaction between compositing system, so it is important to design maglev system considering the character of magnetic levitation controller in order to get the required performance of Maglev. The factors affecting the levitation controller of maglev are the dynamics of levitation magnet, the carrying weight of the overall system, the normal force and lateral force of traction motor and rail condition. In this paper the interaction between magnet and vehicle weight is analysed on side of stability of levitation controller in order to get the required performance of levitation controller.

• Proceedings of the KSR Conference
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• 1998.05a
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• pp.338-348
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• 1998

The study was carried out about the design and the performance study of brake system for Korean High Speed Train of maximum operating speed of 350km/h. The brake system was studied to two parts the function of brake system and the performance of brake system base on Korean-TGV. According to the simulation of brake system, the train should be provided the eddy current brake system for maximum operating speed of 350km/h. The eddy current brake system take charge of about 31% on normal condition and about 22% on emergency by condition. The performance study of brake system would be continued for definition of adhesion factor un friction factor assumed to analysis and simulation.

• Proceedings of the KSR Conference
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• 2006.11b
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• pp.974-980
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• 2006

The government makes an effort to disperse the centralization of Seoul through the its surroundings development for relieving the various social problems caused by the capital region concentration. But, the planless development of rail system in the capital region have made it difficult to approach into Seoul city center from its surroundings. Through Seoul metro line 9, constructed by private company first in Korea, that has operation plan with normal and express train together, we would like to study up on promotion of passenger service quality such as "the improvement of the accessibility to Seoul city center from its surroundings" and "service of various pattern of trains"

• Proceedings of the KSR Conference
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• 2006.11b
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• pp.565-580
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• 2006

Set in constant increase and period current of lively technical development of railroad use and construction of cable stayed bridge railway bridge, one of bridge form of most suitable that think side police officer and the material enemy of bridge that use long rail, is increasing laying stress on the foreign countries. Main tower fixing department of this cable stayed bridge is consisted of main tower flange that support bearing plate, bay ring plate bearing plate, support end rib and diaphragm etc, as stress transmission mechanic that tensility of cable socket into normal force of main tower, and is used this time. These structural elements is very complex the structure and direction of load delivered from socket specially calbe particularly be different, and need FEM analysis that use Thick Shell element for suitable arrangement of mutual stress flowing grasping and absence that follow hereupon because all of the each support plate angle that suport this differ.

• Journal of the Korean Society for Railway
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• v.7 no.1
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• pp.49-54
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• 2004

Particularly derailing freight wagon, which are loaded with dangerous chemicals, has large damages on humans and environment. In this paper the dynamic characteristic of the laminated leaf spring under extreme situation, for example derailment, is examined. The leaf spring has a static hysteresis. Not only the friction value, but also the spring rate are influenced by this hysteresis characteristic. Because of the static hysteresis of the leaf spring the spring rate must be used in normal operation depending upon the loading and the kind of the excitation with the up to 10-fold value of the static spring rate. Some characteristics of the leaf spring can be treated like well-known viscous damping, but fer special situation (preload and/or excitation) particular calculation are necessary.

• Proceedings of the KSR Conference
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• 2008.11b
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• pp.1132-1137
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• 2008

Automatic Operation based on ATO (Automatic Train Operation) is necessary for driverless Light Rail Transit business. When this kind of driverless LRT operation plan is made, TPS (Train Performance Simulation) is traditionally simulated at all-out mode and coasting mode based on manual operation. Commercial schedule speed equals to all-out speed minus $9{\sim}15%$ make-up margin. Coasting mode TPS simulation is also run at commercial schedule speed to calculate run time and energy consumption. But TPS based on manual operation should make an improvement on accuracy in case of driverless LRT operation Plan. In this paper, new fast mode TPS simulation using ATO pattern is proposed and show near actual ATO result. The actual ATO pattern can be accurately simulated with the introduction of 4 parameters such as commercial braking rate, jerk, station stop profile and grade converted distance. Normal mode TPS simulation for commercial schedule speed can be designed to have fast mode trip time plus 3 seconds/km margin recommended by korean standard LRT specification.

• Proceedings of the KSR Conference
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• 2011.05a
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• pp.680-689
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• 2011

A dynamic analysis procedure is developed to provide a comprehensive estimation of the dynamic response spectrum for locomotive's wheels running over a Pre-Stressed Concrete (PSC) box girder bridge on the Korea high speed railway. The wheel force spectrum with the bridge behavior are analyzed as the dynamic procedure for various running speeds (50~450km/h). The high-speed railway locomotive (KTX) is used as 38-degree of freedom system. Three displacements(vertical, lateral, and longitudinal) and three rotational components (pitching, rolling, and yawing). For one car-body and two bogies as well as five movements except pitching rotation components for four wheel axes forces are considered in the 38-degree of freedom model. Three dimensional frame element is used to model of the PSC box girder bridges, simply supported span length of 40m. The irregulation of rail-way is derived using the exponential spectrum density function under assumption of twelve level tracks conditions based on the normal probability procedure. The dynamic responses of bridge passing through the railway locomotive with high-speed analyzed by Newmark-${\beta}$ method and Runge-Kutta method are compared and contrasted considering the developed models of bridge, track and locomotive comprehensively. The dynamic analyses of wheel forces by Runge-Kutta method which are able to analyze the forces with high frequency running on the bridge and ground rail-way are conducted. Additionally, wheel forces spectrum and three rotational components of vehicle body for three typical running speeds is also presented.

• Journal of Science and Technology Studies
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• v.10 no.2
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• pp.77-105
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• 2010

This essay aims to look into the possibility and limit of a technological fix with the PSD (platform screen door), which was proposed as the solution of subway risk problems. Subway risk problems may be classified into five categories-on-rail accidents, in-station accidents, platform accidents, spatial risks in underground, and risks due to a crime or terror-, and the platform accidents, which happens at the interface between the rail and the station, is the most serious and prominent. The PSD is considered as an effective technical means to prevent platform accidents. However, there remains a possibility of aggravating unexpected and invisible risks. When a fire breaks out in platforms, especially at exchange stations during the rush hour, the PSD can become a "wall of outcrying", since it may act as the "safety shutter" which killed many people in the 2003 Daegu subway disaster. This is why we need to look into the limit of a technological fix with the PSD.

• Structural Engineering and Mechanics
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• v.68 no.1
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• pp.67-80
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• 2018

Recently, U-section decks have been more and more used in metro and light rail bridges as an innovative concept in bridge deck design and a successful alternative to conventional box girders because of their potential advantages. U-section may be viewed as a single vent box girder eliminating the top slab connecting the webs, with the moving vehicles travelling on the lower deck. U-section bridges thus solve many problems like limited vertical clearance underneath the bridge lowest point, besides providing built-in noise barriers. Beam theory in mechanics assumes that plane section remains plane after bending, but it was found that shearing forces produce shear deformations and the plane section does not remain plane. This phenomenon leads to distortion of the cross section. For a box or a U section, this distortion makes the central part of the slab lagging behind those parts closer to the webs and this is known as shear lag effect. A sample real-world double-track U-section metro bridge is modelled in this paper using a commercial finite element analysis program and is analysed under various loading conditions and for different geometric variations. The three-dimensional finite element analysis is used to demonstrate variations in the transverse bending moments in the deck as well as variations in the longitudinal normal stresses induced in the cross section along the U-girder's span thus capturing warping and shear lag effects which are then compared to the stresses calculated using conventional beam theory. This comparison is performed not only to locate the distortion, warping and shear lag effects typically induced in U-section bridges but also to assess the main parameters influencing them the most.