• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.10
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• pp.81-87
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• 2017

This paper describes the dynamic behavior and enhancement of Korean high-speed trains. The tail vibration reduction method of the yaw damper installation method change, which was derived from previous research, was applied to the running test of high-speed train. In addition, the vibration reduction method for the entire vehicle was derived by a numerical method and its effect was confirmed by a running test. The improved design was applied to the double-deck high-speed train coaches and the commissioning proceeded without problems in dynamic behavior. Sensitivity analysis of the suspension parameters affecting the critical speed of Korean next-generation high-speed trains was performed and four design variables that greatly affected the critical speed were derived. These were in the order of the primary elastic joint x-directional stiffness, the secondary yaw damper series stiffness, the secondary lateral damper damping coefficient, and the carbody damper damping coefficient. By optimizing the design variables, the suspension parameter that improves the critical speed by 23.3% can be used in the commercial designs of Korean next-generation high-speed trains.

• Proceedings of the KSR Conference
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• 2004.06a
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• pp.915-920
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• 2004

We have studied the technologies for a double-deck train. But, there are no standards and test methods for a double-deck train. Therefore, we apply the standard and test method of the general train to transform the structural analysis of a double-deck train. This study is the result of a structural analysis by the finite element method for double-deck train carbodies. The results of the study can be used as basic guidelines in designing double-deck trains in the future.

• Journal of the Korean Society for Railway
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• v.13 no.2
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• pp.208-213
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• 2010

This paper describes the instruments used, and the test procedures adopted, and the findings obtained from a research project aiming to investigate, via full-scale field tests, the ground borne vibration caused by underground railway tunnel constructed in hard rock. The ground borne vibration induced by high-speed trains (i.e. the Korea Train eXpress (KTX) services) with a speed of approximately 200km/hr was measured inside the borehole constructed in the close proximity to the KTX tunnel using 3-component borehole seismographs in order to investigate the wave propagation of ground borne vibration. This paper also discusses the limitation associated with the current practice of measuring ground borne vibration using conventional borehole seismograph.

• Proceedings of the KWS Conference
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• 2000.04a
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• pp.228-231
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• 2000

Based on the principle of complementary energy an analytical method is developed for determining thermal stress distribution in an thermal barrier coating. This method gives the stress distributions which satisfy the stress-free boundary conditions at the edge. Numerical examples are given in order to verify the method and to investigate the thickness effects of the ZrO$_2$-8wt％Y$_2$O$_3$ top coat on the integrity of thermal barrier coating consisted of IN738LC substrate and MCrAlY bond coat.

• Proceedings of the KWS Conference
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• 2004.05a
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• pp.223-225
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• 2004

Based on the principle of complementary energy an analytical method is developed for determining thermal stress distribution in an thermal barrier coating. This method gives the stress distributions which satisfy the stress-free boundary conditions at the edge. Numerical examples are given in order to verify the method and to investigate the thickness effects of the ZrO$_2$-8wt%Y$_2$O$_3$ top coat on the integrity of thermal barrier coating consisted of IN738LC substrate and MCrAlY bond coat.

• Korean Journal of Materials Research
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• v.10 no.4
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• pp.312-316
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• 2000

A study has been made to investigate the effects of hot isostatic pressing(HIP ping) on bond strength and elevated temperature characteristics of thermal barrier coating(TBC). The specimens were prepared by HIPping of TBC which is composed of the ceramic top coat(8wt%$Y_2$$O_3$-$ZrO_2$) and the metallic bond coat on the matrix of IN738LC superalloy. The results showed that the porosity and microcracks in the ceramic top coat of TBC were significantly decreased by HIP. As a result, the bond strength of the HIPped coating was increased above 48% compared to that of as-coated specimen and microstructure was homogenized. It was found that the thermal cycle resistance of HIPped coating was inferior to that of as-coated specimen. It was considered that this result was mainly caused by the reduction of internal defects in the top coat layer which could play a role in relaxing the thermal stress due to a large difference in thermal expansion between TBC and matrix.

• Proceedings of the KSR Conference
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• 2004.06a
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• pp.811-818
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• 2004

This report was studied about the design of formation and layout of major components of double deck train operated at main line of the domestic. And we carried out the basic design of train formation, the layout of propulsion system and brake system and studied about the performance of train traction and brake system of double deck train.

• Proceedings of the KSR Conference
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• 2007.11a
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• pp.1018-1023
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• 2007

Recently, a double deck train is considered as the one of solutions for efficient and comfortable railroad transportation systems on busy lines without any big investment on existing railroad infra-structures in many countries. However, prior to the operations of double deck trains on existing lines, careful investigations should be performed since the double deck trains have big cross sections, high mass centers and no enough spaces for mounting electric equipments. In this paper, several operational cases of double deck trains in other countries have been reviewed for preparing double deck train operations in Korea.

• Proceedings of the KIEE Conference
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• summer
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• pp.1346-1348
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• 2004

In this paper, Traction system and electric devices of double deck is designed to examine technical reasonableness for driving on the ground and underground. Other countries's double decks is considered. For designing the electric devices, two accelerations are considered and design criterion are given.

• Proceedings of the KIEE Conference
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• 2005.07b
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• pp.1622-1624
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• 2005

In this paper, traction system of a double deck train were designed to examine technical reasonableness for driving on the ground and underground. Double deck trains operated in other countries were also considered. For designing the electric devices, two types of accelerations and electric devices arrangements which are based on the current subway system were considered.