• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.313-316
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• 2008

Corrosion of steel in the reinforced concrete structures is one of the main reason of degradation. It causes that lifetime of structures is shortened and maintenance cost is increased. And it also causes degradation of structures like bridges which are under repeated load. So, many research have been performed about FRP rebar. But there are few research about FRP rebar under fatigue. This study is to examine flexural characteristic of concrete beam reinforced with FRP(CFRP, GFRP) rebar under static and fatigue for considering the application. The specimens that used in this study are designed by ACI 440.1R-06 and reinforced with CFRP(CR) or GFRP(GR) overly. In the result of static bending test, all specimens were failed at compression phase. In fatigue test, the fatigue stress level was 60%, 70% or 80% of the static bending strength. Most of the specimens seemed to be compressive failure, but CR-60 and CR-70 specimens were failed with rupturing of tension bar.

• Computational Structural Engineering
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• v.5 no.2
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• pp.12-17
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• 1992

지진하중에 대한 내진성능을 평가하기 위하여 유사동적 실험기법은 다양한 시험체를 대상으로 응용되어 왔다. 특히 실물크기의 시험체에 대한 실험이 가능하다는 특징 때문에 substructuring기법을 도입하여 부분구조물에 대한 유사동적실험이 활발히 진행되고 있으며, substructuring기법에 사용되는 수치적분 알고리즘의 효율성 및 새로운 보완이 필요한 것으로 판단된다. 근래에 구조물의 진동제어(vibration control)를 목적으롤 개발된 rubber bearing, viscous damper 등은 두드러진 감쇠특성을 갖고 있는 장치로서 strain-rate 효과에 비교적 민감하다. 지금까지의 유사동적실험을 준정적으로 실험이 수행되었으나, 이러한 장치가 설치된 구조물의 진동제어 성능실험을 위해서는 가능한 실시간(real time)에 가까운 실험 진행속도를 갖는 것이 유리하다. 최근에 Nakashima는 digital servomechanism을 이용하여 실시간에 가까운 실험속도의 유사동적 실험을 수행하였으며, 이에 대한 지속적인 연구를 진행하고 있다.

• 전기의세계
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• v.31 no.3
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• pp.187-190
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• 1982

발전효율은 증기발생용 수질 보일러의 구조 및 재질 등 여러가지가 있겠으나 그중 연료의 연소효율이 가장 중요하여 이것과 관련한 성상 및 연료현상에 대하여 기술하고 또한 국내에서는 이를 성능시험에 대한 제도적 장치 및 기법이 확립되어 있지 않아 성능 기준의 판정이 곤란한 실정이므로 측정 방법도 간단히 부연하였다.

• Journal of the Korean Geotechnical Society
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• v.40 no.4
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• pp.113-126
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• 2024

Shotcrete lining is an important material for the stability of tunnels in NATM tunnels. However, stressmeters for stress measurements of shotcrete lining are installed in the field without performance verification because of a lack of research on methods, procedures, regulations, and reliability of measurement equipment. To solve this problem, all shotcrete stressmeters currently used in Korea were investigated. For each stressmeter, external inspection and structural and functional inspection were performed to identify defects and problems in devices. For this purpose, a shotcrete stressmeter performance test device capable of load loading in stages was developed and obtained KOLAS certification. Using the device, stressmeter performance tests were conducted. Structural problems of integrated- and cell-type shotcrete stressmeters were identified through concrete mold tests, and improvement plans and performance verification procedures were suggested. The results of this study are expected to contribute to the preparation of regulations for the performance verification of shotcrete stressmeters and the selection of measuring instruments in the field in the future.

• Proceedings of the Korean Information Science Society Conference
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• 2000.10c
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• pp.621-623
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• 2000

클러스터를 구성하는 단위 노드로 SMP가 새로운 대안으로 시장에 등장하였다. 이러한 멀티프로세서 클러스터(CLUMP)는 하나의 시스템에 다중 메모리 구조를 가지는데, CLUMP가 가지는 다중 메모리 구조를 효과적으로 사용하기 위해서 본 논문에서는 중첩된 병렬화 프로그램 모델을 제안하였다. 중첩된 병렬화 모델은 중첩된 루프 레벨의 병렬화, 중첩된 태스크 레벨의 병렬화, 그리고 다중 중첩된 병렬화로 나뉜다. 본 논문에서는 중첩된 루프 레벨의 병렬화를 실험대상으로 하여 그 성능을 평가하고 단일 메모리 구조의 병렬화 프로그램과 성능을 비교하였다. 실험 결과 시험한 중첩된 병렬화 모델이 단일 메모리 구조의 병렬화 프로그램에 비하여 좋은 성능을 나타내었지만, 실험대상이 된 루프 레벨 병렬화의 잠재적인 특징으로 인해 실행에 참여하는 노드 수가 많아질수록 성능 향상 폭이 감소하는 결과를 보였다. 프로그램의 성능 향상 폭과 확장성은 문제 크기가 클수록 좋은 특성을 보였다.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.41 no.11
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• pp.891-899
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• 2013

This paper suggests a test and evaluation procedure of conformal load-bearing antenna structure(CLAS) for high speed military jet application. A log periodic patch type antenna was designed for multi-band communication and navigation antenna. Carbon/Glass fiber reinforced polymer was used as a structure supporting aerodynamic loads and honeycomb layer was used to improve antenna performance. Multi-layers were stacked and cured in a hot temperature oven. Gain, VSWR and polarization pattern of CLAS were measured using anechoic chamber within 0.15~2.0 GHz frequency range. Tension, shear, fatigue and impact load test were performed to evaluate structural strength of CLAS. Antenna performance test after every structural strength test was conducted to check the effect of structural test to antenna performance. After the application of new test and evaluation procedure to validate a new CLAS, a design improvement was found.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.11
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• pp.7244-7249
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• 2015

In this study, in order to asses the structural performance of trapezoidal PSC girder using a socket joint system and it is possible to calculate the optimized cross-section of the web element tests were carried out for each specimens. we conducted a socket joint performance test, web bending and shear performance tests and all tests were performed at 4 point loading method. The initial crack load of socket joint specimen was significantly lower than the reference specimen but post peak behavior was no significant differences. And the length of the loop joint of the reinforcing bars had no significant effect on the maximum load. As a web shear tests, to obtain a maximum load of the specimen has a prestressing rod reinforced at tension side. As a web flexural tests, to obtain higher diagonal cracking load in specimen of reinforced using prestressing rod than reference specimen.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.145.2-145.2
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• 2010

탄소복합소재 분리판의 연료전지 성능을 시험하기 위해 소형 고분자연료전지 스택을 제작하였으며 연료전지 운전에 따른 성능변화를 측정하여 탄소복합소재 분리판이 연료전지 스택의 성능에 미치는 영향을 조사하였다. 자체 설계한 가스유로로 디자인된 분리판과 MEA를 적층한 스택의 초기 성능과 장기간 운전에 따른 전압 감소를 측정하였다. 또한 장시간 운전 동안 각 셀의 전압 거동도 함께 측정하였으며 비교를 위해 흑연 분리판을 이용하여 제작한 스택의 성능도 함께 시험하였다. 스택에서 각 셀의 성능은 단위전지에서의 성능과 유사하게 나타나 분리판과 스택의 구조가 셀의 성능을 충분히 보여줄 만큼 적절히 디자인된 것을 알 수 있었으며, 장시간 운전 동안 전류가 증가함에 따라 스택의 성능 감소도 점차 증가하였으며 두 종류의 스택이 유사한 성능 감소를 보여 자체 제작한 탄소복합소재 분리판이 흑연 분리판과 유사한 성능을 보임을 알 수 있었다.

• Fire Science and Engineering
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• v.24 no.6
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• pp.82-88
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• 2010

Major structural elements such as columns and beams are designed to withstand the vertical and horizontal loads. Futhermore, when the structural elements were engulfed with fire the structural stability should be stand without failure. The beams have been developed in aspects of structural stability but an evaluation of fire performance was not done. So the data of fire resistance performance of beams filled with concrete at web on H-section is not known. The purpose of this paper is to analyse the correlation between temperature analysis and fire test with the beams and to show the fire resistance performance with two methods.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.11a
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• pp.111-114
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• 2010

MOV(Main Oxidizer shut-off Valves) control the combustion of launch vehicle systems by the supply and the isolation of liquid oxygen to a main combustion chamber in launch vehicle systems. Moreover, the MOV should secure a constant flow rate of liquid oxygen for combustion instability in the steady operational state. To modify the middle flange and rip of inlet valve design by Computer Aided Structural Analysis for improvement of EM core functions. In result, it has been verified to improve performance of EM by tests.