• Archives of design research
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• v.16 no.4
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• pp.185-196
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• 2003

The demand for an environment-friendly transportation system, equipped with low energy consumption, and low-or zero-pollution has been on the increase since the beginning of the World Trade Organization era. Simultaneously, the consistent growth of high-speed tram technology, combined with market share, has sparked a fierce competition among technologically-advanced countries like France, Germany, and Japan in an effort to keep the lead in high-speed train technology via extensive Research and development(R＆D) expenses. These countries are leaders in the race to implement the next-generation transportation system, build intercontinental rail way networks and export the high-speed train as a major industry commodity. The need to develop our own(Korean) 'high-speed train' technology and its core system technology layouts including original technology serves a few objectives: They boost the national competitive edge; they develop an environmental friendly rail road system that can cope with globalization and minimize the social and economic losses created by the growing traffic-congested delivery costs, environment pollution, and public discomforts. In turn, the 'G7 Project-Development of High Speed Railway Technology' held between 1996 and 2002 for a six-year period was focused on designing a domestic train capable of traveling at a speed of 350km/h combined and led to the actual implementation of engineering and producing the '2000 high-speed train:' This paper summarizes and introduces one of the G7 Projects-specifically, the design segment achievement within the development of train system engineering technology. It is true that the design aspect of the Korean domestic railway system program as a whole was lacking when compared with the advanced railroad countries whose early phase of train design emphasized the design aspect. However, having allowed the active participation of expert designers in the early phase of train design in the current project has led to a new era of domestic train development and the implementation of a way to meet demand flexibly with newly designed trains. The idea of a high-speed train in Korea and its design concept is well-conceived: a faster, more pleasant, and silent based Korean high-speed train that facilitates a new travel culture. A Korean-type of high-speed train is acknowledged by passengers who travel in such trains. The Korean high-speed prototype train has been born, combining aerodynamic air-cushioned design, which is the embodiment of Korean original design of forehead of power car minimized aerodynamic resistance using a curved car body profile, and the improvement of the interior design with ergonomics and the accommodation of the vestibule area through the study of passenger behavior and social culture that is based on the general passenger car.

• Journal of the Korean Society for Railway
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• v.17 no.3
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• pp.157-164
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• 2014

The contact force between the pantograph and the catenary is a key factor determining the current collection quality, as they can ensure stable electrical power to the train. In this study, we analyzed the dynamic contact force for HEMU-430X depending on the train speed. It was confirmed through the results that the standard deviation of the contact force increases with an increase in the train speed. It was also verified that the span of the catenary system is a very important factor with regard to the contact force when analyzed with frequency analysis. To secure stable power in speed that exceeds 400km/h, the statistical variation of the contact force should be minimized. To realize this, the catenary tension was increased and the mass of the pan-head was decreased. The ensuing effects were then quantitatively analyzed in terms of the contact force. In addition, the differences in the contact force between a tunnel and an open field were analyzed based on a frequency analysis.

• Journal of the Korean Society for Railway
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• v.15 no.4
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• pp.315-322
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• 2012

In a tunnel, interior noise of a high speed train increases by 5dB~7dB. The reason is that the sound intensity of the acoustic field in the tunnel significantly increases by the reflected waves occurred in the closed space. Especially, the incident acoustic power largely increases on the outside of the compartment side panel and large transmission of noise is available through the side panel and the glass window. In this paper, the sound insulation strategy in the tunnel is proposed for the next generation high speed train under development. Specimens of the aluminum extruded panels, layered panels and double glazed window are manufactured and intensity transmission loss is measured according to ASTM E2249-02. Based on the measured data, problems in the sound insulation performance are diagnosed and the sound insulation strategy is reviewed on each panel and layered structures.

• Steel and Composite Structures
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• v.37 no.3
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• pp.291-306
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• 2020

The noise from the elevated lines of rail transit has become a growing problem. This paper presents a new method for the rapid prediction of the structure-borne noise from steel or composite bridges, based on the receptance and Statistical Energy Analysis (SEA), which is essential to the study of the generation mechanism and the design of a low-noise bridge. First, the vertical track-bridge coupled vibration equations in the frequency domain are constructed by simplifying the rail and the bridge as an infinite Timoshenko beam and a finite Euler-Bernoulli beam respectively. Second, all wheel/rail forces acting upon the track are computed by taking a moving wheel-rail roughness spectrum as the excitation to the train-track-bridge system. The displacements of rail and bridge are obtained by substituting wheel/rail forces into the track-bridge coupled vibration equations, and all spring forces on the bridge are calculated by multiplying the stiffness by the deformation of each spring. Then, the input power to the bridge in the SEA model is derived from spring forces and the bridge receptance. The vibration response of the bridge is derived from the solution to the power balance equations of the bridge, and then the structure-borne noise from the bridge is obtained. Finally, a tri-span continuous steel-concrete composite bridge is taken as a numerical example, and the theoretical calculations in terms of the vibration and noise induced by a passing train agree well with the field measurements, verifying the method. The influence of various factors on wheel/rail and spring forces is investigated to simplify the train-track-bridge interaction calculation for predicting the vibration and noise from steel or composite bridges.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.415.2-415.2
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• 2016

Triboelectric nanogenerator (TENG) is one of ways to convert mechanical energy sound, waves, wind, vibrations, and human motions to available electrical energy. The principal mechanism to generate electrical energy is based on contact electrification on material surface and electrostatic induction between electrodes. The performance of TENG are dependent on amount of the input mechanical energy and characteristics of triboelectric materials. Furthermore, the whole TENG system including mechanical structure and electrical system can effect on output performance of TENG. In this work, we investigated the effect of gear train on output performance and power conversion efficiency (PCE) of TENG under a given input energy. We applied the gear train on mechanical structure to improve the contact rate. We measured the output energy under a constant input energy by controlling the size of the working gear. We prepared gears with gear ratios (rin/rw) of 1, 1.7, and 5. Under the constant input energy, the voltage and current from our gear-based TENG system were enhanced up to the maximum of 3.6 times and 4.4 times, respectively. Also, the PCE was increased up to 7 times at input frequency of 1.5 Hz. In order to understand the effect of kinematic design on TENG system, we performed a capacitor experiment with rectification circuit that provide DC voltage and current. Under the input frequency of 4.5 Hz, we obtained a 3 times enhanced rectifying voltage at a gear ratio of 5. The measured capacitor voltage was enhanced up to about 8 fold in using our TENG system. It is attributed that our gear-based TENG system could improve simultaneously the magnitude as well as the generation time of output power, finally enhancing output energy. Therefore, our gear-based TENG system provided an effective way to enhance the PCE of TENGs operating at a given input energy.

• 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.

• Journal of Digital Convergence
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• v.10 no.11
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• pp.197-202
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• 2012

Block Train Services(BTS) are actively studied in many countries for higher productivity and eco-friendly systems of inland freight distribution. However it is difficult for an ordinary student or researcher to approach for understanding and studying BTS because rail transport is operated monopolistically by Korea government and most freight information in each company belongs to its business secret due to the industrial characteristics. For such reasons, the study aimed to develop a BTS simulation model that it supports understanding and strategic decision required for BT operation. To build the result, expert depth-interviews were conducted with analysis of relative references through the domestic representative BT operating company K. The simulator refers to the Busan NewPort-Uiwang section and functionally, it supports scenario generation and analysis on BT operation. It makes a contribution to study a new type's technological application for learning and strategic analysis of BTS.

• Journal of the Korea institute for structural maintenance and inspection
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• v.19 no.5
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• pp.1-9
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• 2015

Recently Honam high-speed railroad line is constructed in southern part of Korea. This line is for next generation HST named HEMU-430X. But there is a limestone mine near this line and this mine will make a process to dig a passageway under the railway line. In this case, safety of railroad system and stability of mine are crucial problems on both sides. By measuring mine blasting vibration and calculating regression equation, effect of mine blasting to train running is investigated quantitatively. 0.5 kine (cm/sec) is applied as a management specification of vibration based on field measurement. In this study, changes of blasting patterns are suggested to control vibration of mine blasting. And the effect of train vibration to mine is also invesitigated by numerical analysis.

• Journal of the Korean Society for Railway
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• v.19 no.4
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• pp.409-416
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• 2016

The contact force characteristic between the pantograph and the catenary wire represents the current collection quality of trains; it should be precisely controlled under international standard. Recently, a noise reduction cover has been installed around the pantograph of high speed trains. However, little study on the contact force by the pantograph cover has been conducted. In this study, the impact on the current collection performance of the pantograph cover was analyzed by dynamic contact force measurement using a next generation high speed train (HEMU-430X). As a result, it was confirmed that the attachment of a pantograph cover could lower the mean contact force by approximately 50N at 300km/h. In addition, the pure difference of the average contact force by the presence of pantograph cover, except for the static pressure, was measured and found to be up to 110N at 300km/h. It was also found that the standard deviation of the contact force of 3~5N could be changed by use of a pantograph cover.

• Journal of the Korean Society for Railway
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• v.16 no.1
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• pp.32-39
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• 2013

The next generation high-speed train(HEMU-430X) is Korea's first electric multiple unit type, high speed vehicle resulting from a national R&D project. Tests have been conducted on the Kyungbu High Speed Line running at speeds up to 354.64km/h, and analysis of the dynamic behavior of the train was carried out to evaluate its safety. In this study, a simplified method using an accelerometer(the method specified in UIC 518 OR) was chosen to analyze the safety of the train's dynamic behavior. The section chosen for analysis section was ${\pm}10{\sim}20km/h$ with respect to the maximum speed point. In addition, we analyzed the trend of this dynamic behavior with increasing speed by comparing the analyzed values with those of UIC 518 OR. The dynamic behavior results met the limit values of UIC 518 OR and the study indicates that this trend is predicted to continue at speeds above 354km/h.