• 한국산학기술학회논문지
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• 제20권5호
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• pp.502-509
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• 2019

도로교의 신축이음장치 성능시험에 있어 최근에는 많은 연구가 진행되어 있지만, 항공기 활주로 연결 교량에 있어서 국내에 적용사례가 전무하고 성능시험에 대한 기초자료가 없는 상황이다. 본 연구는 활주로 연결 교량이 건설되어있는 인천공항 2단계 확장공사현장에 국내 최초로 적용된 강재형 모노셀 신축이음장치의 성능평가를 위해 전산해석과 KS F 4425기준에 근거하여 수축 신장 및 반복하중시험을 실시하였다. 시제품 제작 전 설계 문서에 기초하여 Midas 해석프로그램으로 전산 분석하였고 시제품을 제작하여 2001년 KS F 4425기준에 근거하여 완제품 성능시험을 시행하였다. 국내 교량의 하중재하시험에 대한 기술 기준은 대부분 차량에 대한 것이고 항공기에 대한 선례가 없어 인천공항공사에 출입하는 항공기 중에서 축하중이 최대치인 F급 $468.4kN/m^2$를 보수적으로 적용하여 200만회 반복재하시험을 진행하였다. 완제품 결과 제품에는 육안검사로 이상 유 무가 관찰되지 않아 충분한 사용성 및 내구성을 확보하였다고 판단된다. 수축 신장의 경우 2,500회 반복 시험 후 KS F 4425 기준에 따른 육안검사로 이상 유 무가 관찰되지 않아 충분한 신축성을 확보하였다고 판단된다. 본 연구의 결과는 선례가 없는 항공기에 대한 신축이음장치의 성능시험에 있어 유용한 현장 시험 자료 및 전산 해석 결과가 참고자료 활용에 가치가 있을 것으로 기대된다.

• International Journal of Naval Architecture and Ocean Engineering
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• 제8권5호
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• pp.442-455
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• 2016

The resistance and seakeeping performance of a high-speed monohull vessel were investigated through a series of model tests in a towing tank. The hull had a slender wave-piercing bow, round bilge, and small deadrise angle on stern. Tests on the bare hull in calm water were first conducted and tests on spray rails followed. The spray rails were designed to control the flow direction and induce a hydrodynamic lift force on the hull bottom to reduce trim angle and increase rise of the hull. The maximum trim of the bare hull was $4.65^{\circ}$ at the designed speed, but the spray rails at optimum location reduced trim by $0.97^{\circ}$. The ship motion in head seas was examined after the calm water tests. Attaching the rails on the optimum location effectively reduced the pitch and heave motion responses. The vertical acceleration at the fore perpendicular reduced by 11.3%. The effective power in full scale was extrapolated from the model test results and it was revealed that the spray rails did not have any negative effects on the resistance performance of the hull, while they effectively stabilized the vessel in calm water and waves.

• 한국공간구조학회논문집
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• 제19권2호
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• pp.63-72
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• 2019

Wireless sensors are more favorable in measuring structural response compared to conventional sensors in terms of them being easier to use with no issues with cables and them being considerably cheaper. Previous tests have been conducted to analyze the performance of MEMS (Micro Electro Mechanical Systems) sensor in sinusoidal excitation tests. This paper analyzes the performance of in-built MEMS sensors in devices by comparing with an ICP sensor as the reference. Earthquake input amplitude excitation in shaking table tests was done. Results show that MEMS sensors are more accurate in measuring higher input amplitude measurements which range from 100gal to 250gal than at lower input amplitudes which range from 10gal to 50gal. This confirms the results obtained in previous sinusoidal tests. It was also seen that natural frequency results have lower error values which range from 0% to 3.92% in comparison to the response spectra results. This also confirms that in-built MEMS sensors in mobile devices are good at estimating natural frequency of structures. In addition, it was also seen that earthquake input amplitudes with more frequency contents (Gyeongju) had considerably higher error values than Pohang excitation tests which has less frequency contents.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2011년도 제37회 추계학술대회논문집
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• pp.389-392
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• 2011

본 연구에서는 틸트로터 비행체인 스마트무인기의 비행시험에서 엔진성능 데이터를 추출하고 분석하였다. 비행시험은 프롭로터의 틸트각이 90도에서 0도로 변화하고 다시 0도에서 90도로 변환하는 천이비행 영역에서 이루어졌다. 비행시험으로부터 수집된 엔진성능 데이터로서 엔진 동력과 비연료 소모율은 엔진성능계산프로그램의 예측결과와 잘 일치하였다.

• International Journal of Fluid Machinery and Systems
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• 제4권2호
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• pp.229-234
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• 2011

For Lift-type Vertical Axis Wind Turbine (VAWT), it is difficult to evaluate the performance through the scale-model wind tunnel tests, because of the scale effect relating to Reynolds number. However, it is beneficial to figure out the critical value of Reynolds number or minimum size of the Lift-type VAWT, when designing this type of micro wind turbine. Therefore, in this study, the performance of several scale-models of Lift-type VAWT (Reynolds number : $1.5{\times}10^4$ to $4.6{\times}10^4$) was investigated. As a result, the Reynolds number effect depends on the blade chord rather than the inlet velocity. In addition, there was a transition point of the Reynolds number to change the dominant driving force from Drag to Lift.

• 대한기계학회논문집B
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• 제30권11호
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• pp.1117-1122
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• 2006

The PEM type regenerative fuel cell(RFC) for the ground simulator of the regeneration electric power system has been designed, manufactured, and tested. In this paper, the designing and manufacturing procedures of the RFC were presented. Also, the performance test results were showed briefly. The RFC consists of PEM type stack, humidifier, pressure and flow control valve, storage tanks, pump and controller. The performance tests were carried out with stack and system performance tests. The performance targets are more than 50% stack efficiency, 1.5kW stack power, less 400W parasitic power in design condition. Most of the performances required are satisfied.

• 대한기계학회논문집
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• 제9권2호
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• pp.190-201
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• 1985

본 논문에서는 측정된 공작기계의 동적성능은 절삭조건과 공작기계의 동적 컴 플라이언스의 복합적인 함수이므로 공작기계의 동적 성능을 정확히 평가하고 설계.개 선을 용이하게 하기 위하여는 직접절삭시험 중 가진 시험을 동시에 수행하는 방법이 필요하다. 본 연구에서는 선반의 외경 선삭가공중의 동적성능을 직접절삭시험과 가 진 직접절삭법을 통하여 평가하고자 한다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1992년도 한국자동제어학술회의논문집(국내학술편); KOEX, Seoul; 19-21 Oct. 1992
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• pp.165-170
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• 1992

In this paper, the Hardware-In-The-Loop Simulation(HILS) of missile systems are studied. The HILS is an effective performance evaluation technique that bridges the simulation fidelity gap between analytic all-digital simulations and actual flight tests of missile systems. The HILS may be required to perform system integration tests, performance evaluation at system or subsystem level. Major elements of this HILS facility will include the flight table, simulation computers, I/O computer and peripheral equipments. HILS of missile systems typically involve computer modeling of flight dynamics coupled with a hardware guidance and control(G/C) systems. This paper describes a real time performance evaluation technique of a G/C system, Development of a HILS for a Autopilot of SAM G/C will be used as an example.

• 항공우주시스템공학회지
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• 제10권1호
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• pp.111-117
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• 2016

A new configuration of tiltrotor UAV previously suggested by Korea Aerospace Research Institute (KARI) for the purpose of increasing the endurance performance in airplane mode flight has extended wings attached to the nacelle and rotated with the nacelle according to the flight modes. In this research, the effectiveness of the extended wing on the enhancement of the endurance performance of KARI tiltrotor UAV (TR60) was analytically investigated based on CFD analysis results. Flight tests and ground tests of measuring the fuel consumption were also conducted to directly compare the endurance performance for the two configurations of TR60 baseline and TR60 extended-wing model.

• International Journal of Contents
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• 제5권4호
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• pp.75-80
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• 2009

Recently high-speed memory array based on RAM, which is a type of solid-state drive (SSD), has been introduced to handle the input/output (I/O) bottleneck. But there are only a few performance studies on RAM based SSD storage with regard to diverse workloads. In this paper, we focus on the file system for RAM based memory array based NGS (Next Generation Storage) system which is running on Linux operating system. Then we perform benchmark tests on practical file systems including Ext3, ReiserFS, XFS. The result shows XFS significantly outperforms other file systems in tests that represent the storage and data requests typically made by enterprise applications in many aspects. The experiment is used to design the dedicated file system for NGS system. The results presented here can help enterprises improve their performance significantly.