• Proceedings of the KSR Conference
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• 2009.05b
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• pp.233-237
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• 2009

In this study, we suggest that several approaches to evaluate the collision acceleration value of a car in the article 35 and the guideline 16 of Korean rolling stock safety regulation. There are various methods to evaluate collision acceleration such as; a displacement comparison method by the double integration of filtered acceleration data, a velocity comparison method by the integration of filtered acceleration data, an analysis method of time-velocity curve, or a differential method of time-velocity curve. We compared these methods one another using 1D dynamic simulation model composed of nonlinear dampers, springs and bars, and masses. Also, we applied these methods to a hybrid model, which is made of 3D shell element model and 2D collision dynamics model, in order to evaluate whether 1D force-displacement curve modeling for energy absorbing structures have an effect on the collision acceleration levels or not.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.2139-2144
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• 2008

There are eight kinds of railroad vehicles such as KTX, PP(Push-Pull), NEL(New Electric Locomotive), EL(Electric Locomotive), DL(Diesel Locomotive), CDC(Commuter's Diesel Car), VVVF(Variable Voltage Variable Frequency) and Resistance Control Car that Korail corporation presently runs, and a variety of vehicles just like EMU(Electric Multiple Unit) and DMU(Diesel Multiple Unit) currently developed and accepted are running in the near future. However, There is still no design standard of the control stand of cockpit and the same compatibility of forms and control unit arrangements for locomotive engineers because no one has tried to approach in an ergonomic way. It can cause Locomotive engineers to make errors using the machinery. when the new vehicles are adopted, The efficiency of operation will quite fall down due to the separate training of the engineers. Therefore, We'd like to improve the accuracy of manipulating the machinery used by the engineers at all times according to the design standard of ergonomic technology and safety engineering and increase the operational efficiency and the safety of railroad vehicles in order to handle the problems as quickly as we can in an emergent situation.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.11
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• pp.124-129
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• 2017

In this study, we report characteristics of friction stir welding (FSW) technique applied to Al-6005-T6 extruded sheets, which is a common material for railway car bodies. With the welding speed fixed at 300 mm/min, the revolution per minute (RPM) of the rotating tool was varied from 600 to 1800 RPM, with the aim at evaluating the resultant microstructure and mechanical behaviors. Comparison is also made with the conventional Metal Inert Gas (MIG) welding technique. Unlike MIG, no micro-voids were observed for FSW specimens. Hardness measurement revealed that the increased heat input by increasing RPM results in widened heat affected zone (HAZ) and decreased hardness for HAZ due to grain coarsening. Hardness results for the nugget do no show difference. During tensile tests, specimens fractured at HAZ, and increasing rpm led to decrease of the yield stress and tensile stress for the selected RPM range, which is considered to be due to the grain coarsening for HAZ.

• Journal of the Korean Society for Railway
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• v.12 no.6
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• pp.1049-1058
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• 2009

Korea's Rolling stock workshop were established with the introduction of a railway, and became the center of industrial construction in the modern age of Korea. There still exist a lot of Rolling stock workshop buildings in the Youngsan Rolling stock workshop, the representative case of Korean Rolling stock workshop, and especially the study aims to look into modern architectural properties centered on those well-preserved buildings. Korea's Rolling stock workshop were built considering the proper conditions of location such as the neighboring districts from the port to transport vehicles and materials, the place where railroad lines are centralized, the short returning distance of railroad cars for entry and departure, and had the facility layout according to the order of a working process of vehicles, and the unique structure and the section facade shape with proper functions and sizes according to each purpose. In particular, they actively adopted steel-frame structure and reinforced concrete structure, and came to have the initial characteristics of Korea's modern industrial building which is called the structural transition. Therefore, this study aims to highlight the importance of Rolling stock workshop including the Youngsan Rolling stock workshop as industrial architecture heritage in the modern age of Korea.

• Journal of the Korean Society for Railway
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• v.14 no.3
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• pp.203-210
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• 2011

This study formulates the theoretical wheel-set model to evaluate wheel-climbing derailments of rolling stock due to collision, and verifies this theory with dynamic simulations. The impact forces occurring during collision are transmitted from a car body to axles through suspensions. As a result of combinations of horizontal and vertical forces applied to axles, rolling stock may lead to derailment. The derailment type will depend on the combinations of the horizontal and vertical forces, flange angle and friction coefficient. According to collision conditions, the wheel-lift, wheel-climbing or roll-over derailments can occur between wheel and rail. In this theoretical derailment model of wheelset, the wheel-climbing derailment types are classified into Climb-over, Climb/roll-over, and pure Roll-over according to derailment mechanism between wheel and rail, and we proposed the theoretical conditions to generate each derailment mechanism. The theoretical wheel-set model was verified by dynamic simulations.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.8
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• pp.5039-5044
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• 2015

In this study, we evaluated corrosion behavior of a common rolling stock axle material, RSA1, in seawater. 3-electrode electrochemical cell experiment was conducted using artificial sea water, fabricated according to ASTM-D1141 set by American Society for Testing and Materials, where the corrosion current density and corrosion rate were determined to be $18.3{\mu}A/cm2$ and 0.217 mm/yr, respectively, by employing potentiodynamic test method and impedance spectroscopy method. Considering the fact that life time of railway car is ~25 years, the expected corrosion layer depth is 5mm. Constant-current corrosion test was conducted to accelerate the corrosion process, to reach corrosion periods of 1,3 and 4 years based on Faraday's law, followed by tension tests where the reduced specimen gauge cross-section was re-measured for stress calculation. While no apparent corrosion-related changes in mechanical properties were observed in the elastic regime, the reduction in ductility of the material was found to be increased as the corrosion period increased. The results of this study are expected to be basic corrosion data for the design of rolling stock axles, which will be operated in the sea water environment.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.6
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• pp.3731-3735
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• 2015

This study reports the relationship between rollingstock weight and acceleration performance for HEMU-430X, the first electric multiple unit developed in Korea. While maintaining the consumed power, the total train weight was deliberately varied by 2%, by adding and removing weights, and the it was shown that the lighter train was found to have higher acceleration performance and hence better suited for maximum speed tests below the speed of 413km/h. According to the power consumption analysis based on the velocity data collected per 0.1 second, the balanced speed, when the traction force and air resistance become equal, was determined to be 419km/h for HEMU-430X, which is in agreement with tested result. It is expected that the analyses in this study will be utilized for the speed tests in the future.