• Proceedings of the KSR Conference
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• 2011.05a
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• pp.1642-1646
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• 2011

One of the rolling stocks, low floor tram is recognized as the important alternative to improve traffic and environmental problems. There are many advantages of tram transportation system. It has, especially, low construction costs and easy accessibility. Trams operate with vehicles on roadways. The bogie configuration including traction motor of tramcar is different from that of conventional electric trains because tram has lower floor than train. In these reasons, the traction motors of tramcar are exposed to dusts, water and so on. Therefore, motors are designed by totally enclosed type. In this paper, we explain the design and test of totally enclosed traction motor for tramcar. Characteristic tests and temperature-rising tests were carried out in order to predict the performance of motor and the maximum temperature of coil.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.1035-1040
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• 2011

In this paper we deal with a kinetic performance test system using hydraulic cylinder. It is possible to measure only current using the conventional electro-mechanical actuator when the bogie is in the process of the tilting. This makes impossible to measure the force acting on the tilting actuator. In order to overcome this problem a kinetic performance test system using hydraulic cylinder is proposed. The proposed system provide easy kinetic evaluation for the tilting mechanism and evaluation for the co-relation between load acting on the tilting actuator and the moving displacement(strock) of the tilting actuator.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.275-280
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• 2011

Due to high-speed of trains, the track deformation increases rapidly and may lead to track irregularities causing the track stability problem. To secure the track stability, the continual inspection on track irregularities is required. The paper presents a methodology for identifying track irregularity using the NARX neural network considering non-linearity in the train structural system. A simulation study has been carried out to examine the proposed method. Acceleration time history data measured at a bogie were re-sampled to every 0.25m track irregularity. In the simulation study, two sets of measured data were simulated. The second data set was obtained by a train with 10% more mass than the one for the first data set. The first set of simulated data was used to train the series-parallel mode of NARX neural network. Then, the track irregularities at the second time period are identified by using the measured acceleration data. The closeness of the identified track irregularity to the actual one is evaluated by PSD and RMSE.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.1616-1623
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• 2011

The concrete track was applied for Gyungbu 2nd phase high_speed railroad line as a basic track structure. Two track structures, ballasted track and non_ballasted concrete track, have a different train load transfer mechanisms. However, it's rare to see about research results related with it. So, to understand dynamic response characteristics of the concrete track and roadbed, we measured accelerations of carbody and bogie, vertical and lateral load, stress and displacement of rail, and earth pressures of subgrade at ${\bigcirc}{\bigcirc}{\bigcirc}$k930 station of Gyungbu high_speed line during speed up tests before opening it. Based on these measured results, we could evaluate the level of dynamic responses of the track quantitatively.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.2276-2279
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• 2011

The AUTS(Advanced Urban Transit System) are developed by government R&D business. This units are under main line performance test in Daebul test line. Both AC and DC could apply to the AUTS for pantagraph voltage. So main transformer and some high voltage filters are added to the under-frame. As a result the total weight of each car(Mc1-Tp1-M-T-Tp2-Mc2) is different. And axle load is different each other. The main characteristics of AUTS(Advanced Urban Transit System) are as follows. One inverter control one motor, DDM(Dircet Drive Motor), no driving gear, plug no end door, self-steering bogie etc. These matters could be appeared to strange vibration. So vibration test is important. The vibration test performed to Mc1 and Tp1. The results were checked to the up-down direction and left-right direction for acceleration.

• Proceedings of the KSR Conference
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• 2004.06a
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• pp.789-797
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• 2004

The wear and defects on the wheel tread are caused by the interface between wheel and rail, the suspension system on bogie, the track condition and etc, which are interacted with complex mechanism. Because of the difficulty of analysis of wheel and rail interaction, the measuring data are necessary for improvement of wheel design and maintenance of train. On this case study, the pattern of wheel wears and defects are presented and lifetime of wheel and the reprofiling period are estimated on a basis of the measured results.

• Proceedings of the KSR Conference
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• 2004.06a
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• pp.859-864
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• 2004

In this study, we compared the fatigue characteristics of weld metal with those of base metal. Also we examined the influence of heat treatment and weld bead profiles for the fatigue life of weld metals. From the experimental results, it was seen that the fatigue characteristics of welded specimens with a grinded toe of bead are slightly better than those are not grinded. Also the fatigue life is affected more by the stress concentration on the profile change in the weld toe rather than by residual stress influence, because the fatigue characteristic of weld metals was not influenced whether the heat treatment is conducted or not.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.7
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• pp.1309-1316
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• 2002

The purpose of this study is to analyze the effects of the parameters of the suspension system in railway rolling-stock for KT-23 type passenger vehicle. According to the results of simulation and the field test, Optimal condition was obtained for the stiffness ratio of the primary spring and the secondary of the suspension system. When the stiffness ratio was increased, the vibration was increased on the car body and decreased on the bogie, and ride quality are getting worse because of increase of the vertical natural frequency of the car body. The results of this study are usefull to improve the technology of the ride quality of KT-23 type vehicle.

• Smart Structures and Systems
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• v.22 no.2
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• pp.193-200
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• 2018

From the viewpoint of engineering applications, the prediction of the failure of bogies plays an important role in preventing the occurrence of fatigue. Fatigue is a complex phenomenon affected by many uncertainties (such as load, environment, geometrical and material properties, and so on). The key to predict fatigue damage accurately is how to quantify these uncertainties. A Bayesian model is used to account for the uncertainty of various sources when predicting fatigue damage of structural components. In spite of improvements in the design of fatigue-sensitive structures, periodic non-destructive inspections are required for components. With the help of modern nondestructive inspection techniques, the fatigue flaws can be detected for bogie structures, and fatigue reliability can be updated by using Bayesian theorem with inspection data. A practical fatigue analysis of welded bogies is utilized to testify the effectiveness of the proposed methods.

• Proceedings of the KSR Conference
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• 2000.11a
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• pp.674-679
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• 2000

Designing of the squirrel cage AC Traction Motor has many difficulties which has to be small size in order to be suitable into bogie frame, high efficiency and light weight. It means that induction motor for tractive purpose has to be different magnetic and electric loading ratio from industrial induction motor. This paper is devoted to an examination of how this ratio affects overall design concept and hence the main design points for traction motor. Also studied is tile changed coefficients of the magnetic and electric loading ratio squirrel cage induction motor for the traction purpose which has been already identified from tile reference book for industrial purpose induction motor.