• 터널과지하공간
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• 제3권1호
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• pp.40-49
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• 1993

In this study, the indirect estimation method of the support load which is based upon the integrated measuring technique suggested by Kovari was applied to the calculation of support load in the mine roadway. Four test supports were installed in the area where they had to be replaed. Two of those were GI-130 rigid supports and the others were U-26 yieldable supports. The vibrating wire strain gages which were attached inpairs on the steel arch support were used to provide an accurate measurement. Bending moments and normal forces obtained from strain gage pairs were used to calculate the support load. This method was also verified by laboratory bending tests. The results obtained from the back-calculction method showed relatively good agreement with the measured convergence for each crossection.

• 풍력에너지저널
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• 제14권1호
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• pp.14-20
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• 2023

In this study, using the commercial software Bladed developed by DNV for integrated load calculation of wind turbines, the generation of seismic waves according to soil type based on Korea's domestic regulations, and load calculation considering earthquake conditions were performed according to the IEC standard, and load in the main coordinate system of the fixed offshore wind turbine was calculated. By comparing the calculated load with the design load of the fixed offshore wind turbine, the effect of earthquake loads according to soil type on the main components of fixed offshore wind turbines was evaluated. As a result of the evaluation, when an earthquake load on a wind turbine is considered, the effect of the earthquake load is related to the natural frequency of the major components and the magnitude of the adjacent acceleration in the earthquake response spectrum, and the earthquake load differs according to soil type and may exceed the design load.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2011년도 제42회 하계학술대회
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• pp.168-169
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• 2011

The aim of this paper is to present a new algorithm for the load flow problem using modified Newton-Raphson (NR) iteration method and a approach to derive a simple formula to compensate the reactive power at some heavy load bus. The reactive power source used in this research is the DG which is adjacent to the heavy load. Phenomena of low voltages may cause the load flow calculation process to diverge. In modified NR method, low voltages will be detected and corrected before the next iteration. Therefore, the results of load flow calculation process satisfy the voltage constraint i.e. higher than the lower voltage limit or higher than the critical voltage in case the conventional load flow diverges. Linearizing the power network using PTDFs is a simple method with accepted errors. A new value of voltage at the DG terminal is computed in terms of the voltage deviation of load buses. In this approach, solving the entire system is unnecessary.

• 한국태양에너지학회 논문집
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• 제30권6호
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• pp.108-117
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• 2010

Although many researches of simulation programs to predict climate under the current climate change have been performed but more detailed studies of weather date which might influence the load of buildings seem insufficient. In this study, in Incheon are analyzed IES (Integrated Environmental Solutions)6.0, Ecotect 2010, EnergyPlus v4.0's IWEC file and ISO-TRY, the Korean standard weather data provided by the Korean Solar Energy Society for direct normal radiation which is used in load calculation programs. The results show that the radiation of the programs is the same as that of direct normal radiation per month but has a mere difference, compared with the radiation per hour and IWEC has also 77.12% when compared with ISO-TRY, meaning that it could affect load values of buildings when applied to them. And in case of ISO-TRY, it could be judged that the application of test reference year applied by the data measured has higher reliability than IWEC file.

• 한국태양에너지학회 논문집
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• 제33권3호
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• pp.9-16
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• 2013

In this research, the effect of a heating system, which is powered by direct solar energy accumulated in phase change material (PCM) as heat storage material installed on the floor surface, on the cooling load was studied. Cooling load of a test building designed for this research was measured with fan coil unit and factors affecting it were also estimated. Experiments were performed with and without PCM installed on the building floor to understand the effect of the PCM on the cooling load. Additionally, to confirm the experiments results, the prediction calculation formula by average outside temperature and integrated solar radiation was composed using multivariate regression model. The results suggested that the heating system with PCM on the floor surface has the potential to shift electric power peak by radiating heat, stored during the daytime in it, at night, not increasing the total cooling load much.

• 대한기계학회논문집B
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• 제38권4호
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• pp.289-309
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• 2014

풍력터빈 블레이드는 바람의 운동에너지를 기계적 에너지로 변환하는 장치로써 풍력발전시스템의 출력성능, 에너지변환효율, 하중 및 동적 안정성에 영향을 미칠 수 있기 때문에 주요부품으로 분류된다. 따라서 최적의 블레이드 설계결과를 얻기 위해서는 시스템 특성이 고려된 공력-구조 통합설계가 중요하다. 본 연구에서는 풍력터빈 시스템과의 상호작용이 고려된 블레이드 설계절차를 제안하였고, 2 MW 급 블레이드(KR40.1b)의 공력-구조 통합 설계결과를 제시하였다. 또한 전술한 바와 같이 로터 블레이드에 작용하는 극한하중 및 피로하중은 시스템 운전조건에 따라 가변적이므로 시스템통합하중해석을 위한 2 MW 풍력발전시스템 모델링을 수행하였으며, IEC 61400-1 및 (사)한국선급의 풍력발전기술기준에 따라 수행된 하중해석결과를 제시하였다.

• 한국태양에너지학회 논문집
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• 제28권1호
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• pp.1-8
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• 2008

The aim of this study is to develop the photovoltaic simulation program, called SimPV, which can Predict hourly based power generation of various PV modules and conduct an intensive economic analysis with Korean situation. To establish the reliability of the PV simulation results, we adopt the PV calculation algorithm of TRNSYS program of which verification has already well approved. Extensive database for hourly weather data of Korean 16 cities, engineering data for PV system and building load profiles are established. Case study on the 2.5kW roof integrated PV system and economic analysis are presented with the developed program.

• 한국자동차공학회논문집
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• 제4권1호
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• pp.147-154
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• 1996

An one-zone heat release analysis was studied for a 6 cylinder direct injetction compressionignition engine. The heat transfer constants in this anlysis were calibrated to match the measured fuel energy at 1,000 rpm full load, which was the fuel mass multiplied by the fuel's heating value. The integrated gross heat release values were close to the measured fuel energy at various full load operating conditions. The combustion inefficiency from this calculation was proportional to the smoke of exhaust gas.

• 한국가스학회지
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• 제2권4호
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• pp.1-6
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• 1998

중화학 플랜트의 고온고압 요소인 증기 발생기(steam generator)의 드럼, 헤더 및 헤더 스터브 설계에 응력해석에서 부터 도면자동작도, 제작용 서류 자동생성에 이르기까지의 제반설계과정을 체계적으로 연결시킨 설계정보 통합 관리로 단순 설계오류를 줄이고, 또한 설계변경에 대해 신속한 재설계가 가능한 효율적인 설계를 도모하기 위하여 "피로수명을 고려한 헤더스터브 형상설계 모듈", "TRD301을 기초로한 후육내압부 운전조건(기동/정지 조건) 및 수명평가 모듈", "헤더 및 드럼부 자동작도 모듈"을 개발하였다. 이에 따라 형상설계 모듈을 이용하여 설계된 스터브 형상을 토대로 수명평가 모듈로 수명을 평가한 후 상세설계 도면 및 관련 서류의 자동작도로 이어지는 일관된 종합설계 시스템을 구축하였다.

• Structural Engineering and Mechanics
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• 제28권4호
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• pp.461-477
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• 2008

An adaptive finite element method for analyzing two-dimensional and axisymmetric nonlinear elastic fracture mechanics problems with cracks is presented. The J-integral is used as a parameter to characterize the severity of stresses and deformation near crack tips. The domain integral technique, for which all relevant quantities are integrated over any arbitrary element areas around the crack tips, is utilized as the J-integral solution scheme with 9-node degenerated crack tip elements. The solution accuracy is further improved by incorporating an error estimation procedure onto a remeshing algorithm with a solution mapping scheme to resume the analysis at a particular load level after the adaptive remeshing technique has been applied. Several benchmark problems are analyzed to evaluate the efficiency of the combined domain integral technique and the adaptive finite element method.