• 한국전기전자재료학회논문지
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• 제19권3호
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• pp.280-286
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• 2006

As a way to expand electric capacity in conductor with electric power demand, STACIR/AW (Super Thermal-resistant Aluminum-alloy Conductors Aluminum-clad Invar-Reinforced) conductor which has high electric current and heat resistance characteristics have been developed. STACIR/AW power line is mechanical composite wire composed of steel cores for dip control and aluminum conductors for sending electric current. Recently, to ensure stable operation and prediction of wire life span of STACIR/AW conductor, a heat property of STACIR/AW conductor have been investigated. In the present work, a change of essential property with long term-heat exposure of STACIR/AW conductor and its structure material, INVAR wire and Al conductor, have been investigated. INVAR/AW is approximately $3.2\;{\mu}m/m^{\circ}C$. thermal expansion coefficient of INVAR/AW wire increases with time of heat exposure. the thermal expansion coefficient of INVAR/AW is markedly influenced by heat and mechanical treatment. creep rate(0.242) of STACIR/AW $410\;mm^2$ conductor at room temperature is much higher than that(0.022) at $210\;^{\circ}C$ STACIR/AW $410\;mm^2$ conductor has minimum creep rate at operating temperature. To lower creep rate with increase temperature is more unique characteristics in STACIR/AW. It is expected that STACIR/AW turned its tension to INVAR/AW at the transition temperature. at room temperature, the tension apportionment of INVAR/AW in STACIR/AW is about $50\;\%$. but whole tension of STACIR/AW is placed on the INVAR/AW alone of core metal above transition temperature.

• 한국전산구조공학회논문집
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• 제28권6호
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• pp.699-706
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• 2015

이 연구에서는 FBG센서가 내장된 강연선을 포스트텐션 UHPC 교량(길이 11.0m, 폭 5.0m, 높이 0.6m)에 적용하고 약 1년간의 긴장력 장기모니터링 결과를 정리하였다. 그리고 초기 도입 긴장력과 차량재하시험을 통하여 콘크리트 내부 강연선의 긴장력 변화를 계측하고 계측결과에 대한 분석을 수행하였다. 연구결과, 이 연구에서 제안하는 콘크리트 내부 긴장력 측정방법이 공영 중인 교량에서 외력으로 인한 콘크리트 내부의 작은 프리스트레스 변화를 효과적으로 측정할 수 있음을 알 수 있었다. 아울러 장기 계측결과를 이용하여 응력변화에 의한 유효변형률을 정확하게 얻기 위해서는 온도보정에 사용되는 열팽창계수의 선택이 매우 중요함을 알 수 있었다.

• 전자진흥
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• 제4권9호
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• pp.112-116
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• 1984

• 대한기계학회논문집
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• 제17권2호
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• pp.380-384
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• 1993

In precision wire electrode discharge machining by CAD/CAM, it is the most important problem on machining method to determine the wire electrode offset amout from the accurate calculation of discharge gap in order to increase the machining accuracy, after fixing the main machining conditions such as machining speed, wire tension, coolant conductivity, gap vlotage. The present study shows the relationships between discharge gap and main machining conditions by means of a series of experiment concerned with the gap using the workpiece of STD 11, and suggests the experimental eguation to calculate the accurate wire electrode offset amount under the given machining conditions for spot workers.

• Journal of Welding and Joining
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• 제18권5호
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• pp.41-48
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• 2000

Dynamic behaviors of the GMAW system are simulated using the short-circuit transfer model and the characteristic equations fir the power supply, wire system and arc. The conventional wire equation, which relates the rate change of the wire extension to the wire feed rate and melting rate, is modified to include effects of the molten drop attached at the wire tip. The modified wire equation describes behaviors of the GMAW system more precisely and provides information about the initial bridge volume for short-circuit transfer. The proposed short-circuit model predicts the variation of parameters such as the current, voltage, short-circuit frequency and time considering the effects of the surface tension and electromagnetic force due to current. The calculated results are in broad agreements with the experimental results under the argon shielding condition.

• 한국강구조학회 논문집
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• 제22권2호
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• pp.151-160
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• 2010

최근 기상이변으로 인한 겨울철 폭설로 농가 시설물 중의 하나인 비닐하우스의 붕괴사고가 빈번히 발생하여 농가의 피해가 증가되고 있다. 하지만 이에 대한 정부의 대책이 미약하여 매년 붕괴사고가 일어난다. 프레임 붕괴의 주된 이유는 폭설시 저항할 수 있는 휨내력이 부족하기 때문이다. 본 연구에서는 현재 이용되는 비닐하우스에 인장타이로 보강한 실험연구를 수행하였다. 비닐하우스의 스팬은 6.5m이고, 단면은 두 가지 종류(${\phi}25.4{\times}1.5$, ${\phi}31.8{\times}1.5$)를 사용하였다. 비닐하우스의 곡선 보와 직선 기둥 연결부에 임시적인 인장타이로 스틸와이어와 로프를 이용하여 보강하였다. 프리텐션을 인장타이에 적용시켰고, 적설하중을 등가의 수직하중으로 파괴할 때까지 적용하였다. 무보강과 로프 보강을 비교한 결과 로프 보강의 붕괴하중이 10∼45% 증가하였고 무보강과 스틸와이어 보강을 비교한 결과 스틸와이어 보강의 붕괴하중이 58~73% 증가하였다. 강도와 관련해서는 비교적으로 스틸와이어가 효과적이나, 연결부 및 프리텐션 적용이 로프보다 복잡하고 어려우므로 로프가 더 효율적인 것으로 판단된다.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2000년도 춘계학술대회논문집 - 한국공작기계학회
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• pp.537-542
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• 2000

Wire deflection, surface roughness and roundness were observed on changing discharge time for electrical discharge machining(EDM) of STD-11 in various conditions of thickness. The wire deflection was decreased as increasing discharge time and wire tension. The deflection is the smallest at the speed of wire of 10.6m/min and the water specific resistivity of 5k$\Omega$.cm. The deflection is found to be decreased as increasing dwell time. But if the water pressure is high, it is found not to be changed after the vibration of 4sec. The component of copper(Cu) and zinc(Zn), which is the main material of wire electrode, is observed for rough wire-cutting EDM of STD-11. This phenomena is found to be similar in spite of the change of EDM energy level. But it will be improved by changing the material and the shape of wire. The roundness of middle is found to be worse than that of upper and it is increased as the thickness of material is increased.

• 전기학회논문지
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• 제65권9호
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• pp.1590-1596
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• 2016

In this paper, catenary wires were analyzed aging through the experiment about a new product and a test sample in accordance with temperature changes from long-term use. In case of the contact wire, the maximum load was reduced within 7% and the tensile strength showed a reduced within 6.7% compared with a new reference standard $110mm^2$. 19 Strands of messenger wire have a little more than a standard value, but result data on tensile test were less than the reference value about stranded wire. Also parts among 49 strands of dropper was found to be smaller than the reference value and it appeared greatly increasing intensity as toward the center of the strand.

• 조명전기설비학회논문지
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• 제20권3호
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• pp.78-83
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• 2006

본 연구에서는 통신선 가설 보조 기구인 조가선에 이상 장력이 작용하였을 때 전주의 영향을 유한 요소 해석을 통하여 전주 보호 기구를 설계 해석하여 보호시스템을 개발하였다. 보호시스템은 일반하중 또는 풍압과 일반적인 불평형 하중에서는 조가선이 탈락되지 않고 일정강도 이상이 가해지면 조가선이 자동 탈락되어 전주의 절손 방지 역할을 한다. 이러한 보호시스템의 구조는 유한 요소 해석을 통하여 해석되어졌고, 실제 제품에 대한 인장강도를 측정함으로써 성능을 입증하였다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2006년도 추계학술대회 논문집
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• pp.723-730
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• 2006

In the electrical railway, the tension ascension of contact wire is essential to speed up of train and current collection performance of catenary largely depends on the tension. The tension variation rate of the tensioning device used in existing line limits within 5%, and the tension variation rate of the spring-type tensioning device installed at the section where tensioning length is short bounds within 15%. So it is urgent for us to localize it for high speed line, which the tension variation rate is limited within 3%. Therefore in this study, a pulley-type tensioning device for high speed line is developed. To verify the performance of developed device, a performance test, overload test and failure test is carried out under the code of the Kyung-Bu High Speed line. And it is secured durability performance through a fatigue test.