Papers by Author: Yeon Su Kim

Abstract: An evaluation was carried out by applying a load to the underframe of the freight car to determine the structural strength of the carbody of a newly manufactured freight car for transportation. This study is aimed at evaluating the safety of the underframe of the freight car under the maximum load conditions. The freight car for use in rail freight was designed mainly with SM490A steel and ASTM A441 steel for production. The carbody for rolling stock is a principal structure supporting major underframe equipment and freight. Thus, strength evaluation of this structure is very important. Both structural analysis and loading test were performed under the loading condition. Prior to evaluating structural strength, finite element method software was used for structural analyses of stress distribution in a carbody of freight car. The strain gages were attached on the carbody based on the FEM results. A vertical load test, compressive load test, measurement of deflection amount and a natural frequency measurement test were conducted.

Abstract: The drive shaft of the bi-modal tram has been designed and built into independent wheel drive; all driving wheels are driven by electric motor-gearbox sets independently, in order to make low floor to provide the old and the handicapped with easy access, and to remove differential gears to reduce turning radius. This paper was aimed to evaluate torques on drive shafts while the bi-modal tram was running on slope way in the test track, and at maximum speed in public roadway. On the basis of the torques measured on the drive shafts, torsion characteristics of the independent wheel drive were discussed in this paper.

Abstract: The car body of the bi-modal tram has been designed and built to have low floor to provide the old and the handicapped with easy access considering Korean physical standard, passenger capacity (standee, seated, handicapped), and bus and urban railway regulations in Korea. The car body has been composed of composite materials (light-weight sandwich constructions) with glass epoxy skins, aluminum honeycomb cores and aluminum inner-frames. This paper was aimed to evaluate dynamic characteristics of the car body while the bi-modal tram was running in the test track. Based on the results from vibration accelerations measured on the floor level of centers of car bodies and axle, dynamic characteristics of the composite materials car body were discussed in this paper.

Abstract: For the medium-sized low-floor bus, backbone structure of chassis was designed to have light-weight structure with SAPH (Steel Automobile Press Hot rolled) 440. Strength for the designed backbone structure was also analyzed by finite element method under various dynamic load cases considered in this paper. On the basis of the analysis results, the structural safety for the designed backbone structure was evaluated and discussed in this paper.

Abstract: In the public transport vehicle, vertical and lateral behaviors have a significant effect on ride comfort and safety of passengers on curved track. Based on vertical and lateral vibration accelerations measured on floor level in passenger compartment when the K-AGT ran on the minimum curvature of the 2.4km-test track in driverless mode, expanded uncertainties in measurement were estimated statistically. In addition, vertical and lateral dynamic behaviors of the K-AGT were discussed in this paper.

Abstract: For the designed center frame of low-floor vehicle to have light-weight sandwich structure with glass fabric/epoxy resin skins, aluminum honeycomb cores and steel inner-frames, regression equations for maximum equivalent stresses (Von-Mises stress) and maximum vertical deflection were proposed by finite element analysis. On the basis of the analysis results, the strength and stiffness for the center frame were discussed in this paper.

Abstract: This study was aimed to verify the performance and stability of the 3rd rail type power collector for rubber-tired vehicles. Performance (power interruptions), durability (stresses), stability (vibrations and contact force variations) of the developed power collector were measured and analyzed, while the rubber-tired vehicle ran at various speeds on the test track(about 2.4km).

Abstract: For the designed and manufactured compound CVT that can improve the characteristics of efficiencies and power ratios, realize backward and forward motion including geared neutral without an auxiliary device, various experimental studies have been performed to verify their design validation and theoretical performance analysis. Various comparisons between the theoretical and the experimental results have verified that they can improve the efficiency and speed ratio when compared with the case power circulation mode mechanism and power split mechanism mode are used individually.

Abstract: This study was aimed at evaluating the structural safety of the new bogie frames for Korean-standardized rubber-tired AGT vehicles. The guidance frame and the rotation frame were designed according to Korean-standardized specifications for rubber-tired AGT vehicles, and their stresses were analyzed by using the finite element method. Based on the results of the analysis, dynamic stresses were measured while the train was running under various conditions in the test track. Analytical and experimental results verified the structural safety of the new bogie frames.