• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.05a
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• pp.1232-1240
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• 2001

In this study. a computer simulation of the Korean High Speed Prototype Test Train was performed to investigate the dynamic behavior(running stability. safety and comfort) in detail design process. The simulation model which was prepared by ADAMS/Rail V10.l consists of power car and middle car assembly (2 motorized cars ＋ 3 trailer cars). The nonlinear analysis takes into account the full vehicle model including wheel/rail contact and the influence of disturbed track. Throughout the dynamic calculation of KHST on the straight and the curved track. accelerations in car body. ride comforts and wheel rail forces were investigated.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.11a
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• pp.170-176
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• 2003

The pantograph for Korean High Speed Train was developed and had been evaluating by through "G7- R＆D for home grown high speed train technology". In this study, a relation in mechanical aspect between the train running speed and the current collecting performance of the pantograph is conducted.'for this study, a measuring system for current collecting performance and mechanical characteristics is developed and installed on the prototype Korean High Speed Train, and measurement is conducted while the train runs on the test track. The measuring system is composed of video monitoring system and telemetry & data processing unit. It monitors whether the hazard behavior in the pantograph is occurs or not, and measures acceleration and vertical contact force between the pan head and catenary. Through this study, evaluation of a mechanical vibration characteristics and trend of the pantograph and a interface performance of pantograph - catenary up to 200㎞/h train speed are facilitated.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.23 no.3
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• pp.310-317
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• 2014

The Next-generation High-speed Rail Technology Development Project was started in 2007 by the Korean Government with the aim of developing the core technologies for a high-speed electric multiple unit (EMU) railway system. This is the first attempt to develop a high-speed EMU railway. High-speed EMU trains have superior acceleration and deceleration compared to push-pull high-speed railways such as KTX(Korean Train eXpress). A prototype train was developed and tested on a high-speed line starting in 2012. The new train must maintain running safety during the test. Generally, the international standard (UIC518) is adopted to evaluate the running safety of trains. This method suggests that the test zone must have over 25 sections, and the length of each section must be 500 m. However, it is difficult to implement these test conditions for a real high-speed line. In this study, we analyzed the running safety using several test section lengths (100 m to 500 m) and compared the results. The results of this study will be used to establish a running safety evaluation method for high-speed EMU railways.

• Proceedings of the KSR Conference
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• 2007.05a
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• pp.743-748
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• 2007

The important factor to evaluate the running safety of a railway vehicle would be the interaction force between wheel and rail(derailment coefficient), for which is one of important factors to check the running safety of a railway vehicle that may cause a tragic accident. Especially, a newly developed vehicle that first runs commercially requires necessarily the measurement and evaluation of derailment coefficient for securing the safety of a vehicle while measuring the derailment coefficient in view of securing running safety could be the more important factor than any other factors. In this paper, examined possibility that can forecast derailment possibility to behavior of only vibration and displacement by measuring vibration acceleration and displacement in vehicles that travel actuality rail track, and compares with data of wheel load/lateral force result.

• Proceedings of the KSR Conference
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• 2007.05a
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• pp.1138-1143
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• 2007

Since Maglev vehicle is run over an elevated guideway, the vibrational characteristics of guideway affect the running behavior of the vehicle and guideway. The design of a guideway has a strong effect on the costs of constructing guideways, therefore optimized design of the guideway satisfying running performance is needed for the commercialization of the Maglev vehicle. With an analysis program for dynamics of Maglev vehicles, the dynamic responses of the Maglev vehicle with electromagnet suspension are numerically analyzed according to changes in fundamental natural frequency ratio of a guideway.

• Proceedings of the KSR Conference
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• 2007.05a
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• pp.1091-1096
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• 2007

Since Maglev vehicle is run over an elevated guideway, the structural properties of guideways affect the running behavior of the vehicle and guideway. The design of a guideway has a strong effect on the costs of constructing guideways, therefore optimized design of the guideway satisfying running performance is needed for the commercialization of the Maglev vehicle. With an analysis program for dynamics of Maglev vehicles, the dynamic responses of the Maglev vehicle with electromagnet suspension are numerically analyzed according to changes in fundamental modal damping ratio of a guideway.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.05a
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• pp.200-205
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• 2004

The pantograph for Korean High Speed Train was developed and had been evaluating by through 'G7-R&D project for home grown high speed train technology' In this study, in mechanical aspect, the variation trend of contact force between pantograph and catenary according to the train running speed and driving pattern is conducted. A measuring system for current collecting performance and mechanical characteristics is used for this study, developed and installed on the prototype Korean High Speed Train, and physical characteristics were measured while the KHST runs on the test track. Through this study, remarkable trends of variation are found and analyzed from measured acceleration and vertical contact force between the pan head in pantograph and contact wire in catenary system according to the driving pattern and the train raised a running speed up to 300km/h.

• International Journal of Railway
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• v.2 no.4
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• pp.187-192
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• 2009

Running test of the Korean High-Speed Train using remote controlled measuring system have been executed on the high speed track in order to evaluate and verify the performance of the train. In this paper, influencing factors on the contact force which represents dynamic characteristics between the pantograph and contact wire are analyzed, according to the track condition, span type and running condition. By the analytical study on the test data, we figured out that contact force and dynamic characteristics of the pantograph are mainly affected by running behavior of the train and the span distance which the train passes.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.7
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• pp.175-181
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• 2016

This occurs when the unbalanced rotating body is inconsistent with the mass center line axis geometric center line. Wheelsets are assembled by a single axle with two wheels and a rotating body of a running railway vehicle. Owing to non-uniformity of the wheel material, the wear, and error of the wheel and axle assembly may cause an imbalance. Wheelsets will suffer the effects of vibrations due to the unbalanced mass, which becomes more pronounced due to the thin and high-speed rotation compared to the shaft diameter This can affect the driving safety and the running behavior of a rail car during high-speed running. Therefore, this study examined this unbalanced wheel using a railway vehicle multibody dynamics analysis tool to assess the impact of the dynamic VI-Rail movement of high-speed railway vehicles. Increasing the extent of wheel imbalance on the analysis confirmed that the critical speed of a railway vehicle bogie is reduced and the high-speed traveling dropped below the vehicle dynamic behaviour. Therefore, the adverse effects of the amount of a wheel imbalance on travel highlight the need for management of wheel imbalances. In addition, the static and dynamic management needs of a wheel imbalance need to be presented to the national rail vehicles operating agency.

• International Journal of Railway
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• v.5 no.1
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• pp.10-21
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• 2012

Open steel plate girder (OPSG) bridges are the most prevalent railroad bridge type in Korea, constituting about 40% of all railroad bridges. Solid steel bearings, known as line type bearings, are placed in most OSPG railway bridges. However, the line type rigid bearings generate several problems with the bridge's dynamic behavior and maintenance in service. To compare and investigate the dynamic behaviors of line type, spherical and disk bearings, the vertical displacements of each bearing, including fixed and expansion type, under running vehicles are measured and analyzed. The displacements of disk and spherical bearings are measured after replacing the line type bearings with spherical and disk bearings. This study also analyzed dynamic behaviors of bridges. Furthermore, the deformation of the PTFE (Polytetrafluoroethylene) plate that is placed inside of expansion type spherical and disk bearings is measured and its effect on the dynamic behavior of the bridges is discussed. The up-lift phenomenon at the bearings installed for the steel bridges is estimated. The vertical displacements at mid-span of the bridges are compared according to the bearing types. Finally, the 1st mode natural frequencies are estimated, and the relationship to the vertical displacement is discussed.