• Journal of the Korean Society for Railway
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• v.11 no.3
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• pp.300-310
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• 2008

Through this study, a conceptual design for the next generation high-speed EMU has been derived to meet the crash worthiness requirements of the Korean rollingstock safety regulation. The crashworthiness regulations require some performance requirements for two heavy collision accident scenarios; a train-to-train collision at the relative speed of 36 km/h, and a collision against a standard deformable obstacle of 15 ton at 110km/h. The complete train set will be composed of 2TC-6M with 13 ton axle load, which is different from KTX with the power car of 17 ton axle load. Using theoretical and numerical analyses, a crashworthy conceptual design was derived in terms of mean crush forces and energy absorptions for principal crushable structures and devices. The derived conceptual design was evaluated and improved using one dimensional dynamic simulations for the bar-spring-damper-mass model. It is shown from the simulation results that the suggested conceptual design can easily satisfy domestic crashworthiness requirements.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.12
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• pp.797-803
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• 2019

This study was carried out to reduce the lateral vibration of high-speed electric multiple units. In the study, the high-speed electric multiple unit prototype (HEMU-430X) has a high lateral vibration at low equivalent conicity regardless of the wheel profiles (XP55, GV40, S1002). As wheel wear progresses and the equivalent conicity increases, the lateral vibration tends to decrease. The reason is that a combination of the suspension characteristics causes the body and bogie to resonate at a frequency of 1.4 Hz when the equivalent conicity is low, resulting in body hunting. An investigation of the lateral vibration of overseas high-speed trains showed that a decrease in the hydraulic stiffness of the yaw damper could improve the vibration. The series stiffness of the yaw damper is a combination of the hydraulic stiffness and elastic joint. In this study, an attempt was made to improve the lateral vibration by lowering the stiffness of the elastic joint. The series stiffness of the adjusted yaw damper was approximately 60% compared to the original one. The on track test results showed improvement in the lateral vibration for both running directions. The vibration reduction method of this study can be used for EMU-250 and EMU-320 in future commercial operations.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.973-978
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• 2008

This study concerned on the critical speed due to hunting and snake motion train to ensure the stability. First, the critical speed was calculated by using a numerical model, and calculated the critical speed of the vehicle through the simulation with the use of ADAMS/RAII. Also, the snake motion was confirmed through a modal analysis and running simulation. The calculated results, show that the rail irregularity becomes the influential factors of the stability since it is the direct source of excitation of the vehicle.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.1026-1032
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• 2010

In this paper, To estimate the train exterior noise and environment noise which are occur when High-Speed EMU is driving with the speed of 370km/h, Estimated sound source about noise that is appeared during operation based upon noise SPL values. Based on aero-dynamic noise source and wheel-rail noise source, these were already used to the existed research, we have estimated each sound power about measured noise, and computed the sound source to apply on the High-Speed EMU, and also calculated the sound power in case of the maximum operation speed of 370km/h.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.1006-1010
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• 2010

This paper discusses the numerical study on the stability of the high-speed EMU by developing its lumped parameter model including the effect of the creepage. The 6, 10 and 14 degrees-of-freedom (DOF) lumper parameter dynamic models are developed and the critical hunting speeds calculated from each model via Matlab software are analyzed and compared. It is demonstrated that the critical hunting speeds decrease while the degrees-of-freedom increase. In addition, the parametric study is conducted to extract major design parameters to influence on the stability of the high-speed EMU.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.970-978
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• 2010

In this study, interior noise of the high speed EMU was estimated by statistical energy analysis (SEA) method. Based on the data measured at a distance of 25m from a running train, exterior noise of the running train was calculated. And then it was designed as noise sources in VA ONE, a commercial software of SEA. coupling and damping loss factor of high speed EMU studied in previous studies is used. The interior noise of the train was estimated for a open-land section. The analysis of interior noise of HST in the tunnel section will be estimated through same method.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.1154-1159
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• 2008

Type of the high-speed train under development has been decided to be EMU(electric multiple Units) following the trend of the times, which is weak for vibration and noise due to the distributed traction unit of motors and gears than that of the articulated high-speed train. Also, passengers may feel uncomfortable at high-speed running due to the various vibration of vehicle itself and bogie, especially due to hunting, snake motion of the high-speed train. In this paper, explained was the program to develop the high-speed EMU at every step of basic and detail design and running test, predict and try to reduce the vibration.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.1221-1226
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• 2008

Present, the cooling method of using a phase-change heat transfer such as immersed type, heat pipe etc is applied in cooling of high-capacity power semiconductors of the main power system for the high speed train with the concentrated traction. In order to apply these phase-change cooling system to the high speed EMU to be developed, needed are technological researches of consideration of installing space, air passage, light weight material and miniaturization. Although this research establishes design specifications through theoretical analysis and computational analysis from the basic design process of the cooling system of the propulsion system for the high-speed EMU, when details design is completed, present improvement subject and optimum design before manufacturing the prototype of the cooling system on the basis of analysis results. And then, carried out will be the performance tests through prototype manufacture and reliability estimation by components of cooling system.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.1195-1200
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• 2008

The railway bridge design specification used in our country at present, is reflected results that take into account link between vehicle and roadbed according to decision of TGV vehicle style in 1994, and executes design verification. Hereafter, the particular loading condition and the design speed of the high-speed EMU that is recognized to the next generation of high speed railway, are plain difference with TGV vehicle style decided in 1994. The effect that these load and design speed get in roadbed, especially superstructure, displays difference with the existent high speed railway. The goal of this study is to choose the suitable bridge type, and to reduce the construction cost for the next generation of railway, i.e., the high-speed EMU.

• Proceedings of the KSR Conference
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• 2009.05b
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• pp.465-470
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• 2009

This paper discusses the numerical study on the dynamics of the high-speed EMU by developing the 34 degrees-of-freedom (DOF) lumped parameter model including the effect of the creepage. In order to reflect the creepage, the Kalker's wheel-rail contact theory is introduced in the proposed model. The dynamic analysis using $Matlab^{(R)}$ software is conducted, and its results are compared with those from ADAMS/Rail to investigate the validity of the proposed 34-DOF lumped parameter model. It is demonstrated that the results from the numerical study are similar to those from ADAMS/Rail. In addition, the critical design parameters of high-speed EMU are examined, and the design guidelines for reducing vibration and enhancing ride quality are proposed.