• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2021년도 가을 학술논문 발표대회
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• pp.76-77
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• 2021

compared and reviewed the water repellency and strength characteristics by controlling the surface stamping size and fine aggregate ratio of cement mortar mixed with water repellent as a method to control the ecological imitation surface structure. As a result of measuring the contact angle, the higher the ratio of fine aggregate, the larger the contact angle. The contact angle increased when the surface structure was changed by stamping, and increased as the stamping size became smaller. In the surface stamping of mesh#150, the contact angle was particularly increased.

• 한국정밀공학회지
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• 제29권12호
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• pp.1346-1350
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• 2012

Contact wire is one of the most important components supplying electricity to railroad cars. At the beginning of the research on contact wire, wear problem caused by friction between contact wire and pantograph was considered even more important issue for the failure of contact wire. However, since several fatigue fractures were reported from Shinkansen in Japan, fatigue fracture has become another important issue for the failure of contact wire. Despite of its importance, standard of the fatigue test of contact wire has not been established yet. Thus, fatigue characteristics of contact wire is very difficult issue to evaluate quantitatively. Hence, in this study, test method simulating operating conditions of contact wire by Minsung Kang and etc. is used to evaluate the fatigue characteristics of copper alloy contact wire. Also, test results is compared with the result of Minsung Kang's research on pure copper contact wire.

• 한국초전도저온공학회:학술대회논문집
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• 한국초전도저온공학회 2002년도 학술대회 논문집
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• pp.163-164
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• 2002

We have measured the I-V characteristics and contact resistance of jointed BSSCO tape in the superconducting state. Electrical joint was made by various type of solder. Estimated critical current was about 30 Amp, and the contact resistance of the joint was about 350 nOhm.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 학술대회 논문집 정보 및 제어부문
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• pp.748-750
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• 2004

The pantograph should supply the electrification equipments of a train with the current from the overhead catenary system over a broad range of speeds. For a high-speed electrical train, the dynamic interaction between the pantograph and the overhead catenary system causes the variation of the contact force. As the operational speed increases, the variation of the contact force increases. The contact force variation can cause contact losses, arcing and sparking. If the spark happens between the pantograph and the overhead catenary system, the EMI(electro magnetic interface) and noises may occur. After all, the quality of current collection is deteriorated. This paper deals with the dynamic characteristics analysis between pantograph and catenary system using block pulse function.

• 한국자동차공학회논문집
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• 제18권3호
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• pp.43-52
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• 2010

In this study, the shapes of the wheel and rail are represented by using 3-dimensional surface functions with surface parameters and a 3-dimensional wheel-rail contact analysis is presented. A whole numerical solution of wheel-rail contact at tread and flange including 2-point contacts can be achieved with the proposed numerical algorithm. Kinematic characteristics such as variances of vertical displacement and roll angle, and variance of wheel radius difference for arbitrary yaw and lateral displacement of wheelset, are determined for the KTX wheel-rail pair as an example. The condition of yaw and lateral displacement occurring 2-point contacts to analyze derailment are compared between standard and worn wheels. Differences of contact characteristics between curved and straight rails are also analyzed.

• 한국생산제조학회지
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• 제23권4호
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• pp.368-373
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• 2014

This paper presents the dynamic modeling and analysis results for a spindle supported by angular contact ball bearings (ACBBs) subjected to angular misalignment. Although ACBBs are widely used in spindle systems, their characteristics in regard to angular misalignment have rarely been investigated. A simulation program was developed to calculate the dynamic characteristics of a simple spindle model that is supported by angular contact ball bearings subjected to angular misalignment. Angular misalignment is shown to introduce anisotropy into the angular contact ball bearings and then split the natural frequencies in spindles. Simulations were also performed to show the possibility of evaluating bearing misalignment using natural frequency measurements.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2003년도 추계학술대회 논문집(I)
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• pp.204-209
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• 2003

The railway vehicle is composed of many suspension components, such as 1st springs, 2nd dampers, that have an influence on the dynamic characteristics of high speed train. Also, the wheel/rail shapes and its contact mechanism affect the dynamic behavior of high speed train. but these geometric contact characteristics are nonlinear functions of the wheelset lateral displacement and it do not exact dynamic analysis for high speed train. there is a need to develop a new wheel/rail contact module for dynamic behavior and wheelset model is divided motor box, wheel box and wheel body. This wheel is moved by motor box and constrained by joint. It is almost same a train and its result is more exactly.

• Journal of Mechanical Science and Technology
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• 제16권4호
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• pp.436-447
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• 2002

In this study, the dynamic response of a catenary system that supplies electrical power to high-speed trains is investigated. One of the important problems which is accompanied by increasing the speed of a high-speed rail, is the performance of stable current collection. Another problem which has been encountered, is maintaining continuous contact force between the catenary and the pantograph without loss of panhead. The dynamic analyses of the catenary based on the Finite Element Method (FEM) are performed to develop a pantograph suitable for high speed operation. The static deflection of the catenary, the stiffness variation in contact lines, the dynamic response of the catenary undergoing the force of a constantly moving load and the contact force were calculated. It was confirmed that a catenary model is necessary to study the dynamic characteristics of the pantograph system.

• 전력전자학회:학술대회논문집
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• 전력전자학회 1998년도 Proceedings ICPE 98 1998 International Conference on Power Electronics
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• pp.447-451
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• 1998

This paper conducts a study on a non-contact power delivering system using high-frequency inverter with the purpose of discussing the non-contact electric power transmission characteristics through circuit analysis, magnetic analysis and feasible experiments. In this power delivering scheme, various properties pertaining to the non-contact transformer of the power system such as the design, the core depth, core material, primary side frequency etc. are considered with a view of improving the non-contact power dilivery to the secondary.

• 한국철도학회:학술대회논문집
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• 한국철도학회 1999년도 춘계학술대회 논문집
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• pp.176-184
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• 1999

Dynamic characteristics of pantograph-catenary system that supplies electrical power to high-speed trains are investigated. A simple catenary is composed of the contact and messenger wires connected by hamgers possessing bi-directional stiffness properties. The influences of parameters that determine the contact properties of pantograph-catenary system are investigated through numerical simulations. For the catenary, a finite difference model composed of 10 spans is constructed. The contact and messenger wires are modeled as strings with respective tension and damping ratio values. The pantograph is modeled as a linear 3-degree-of-freedom system. It is found that the tension, number of hangers and damping ratios as well as the speed of the train significantly influence the contact forces and contact separation rate