• 한국태양에너지학회 논문집
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• 제34권5호
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• pp.1-9
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• 2014

Daylight is very useful to control the indoor environment, and can save energy in buildings. So it is necessary to evaluate the daylighting performance of buildings. We proposed a simplified equation that can be used in the early stages of design. And we verified the equation by using the measured illuminance data from the 1/5 scale model. We compared the calculated indoor illuminances and measured illuminance including Daylight Factors of scale model in order to verify the applicability of the simplified equation, and proved the analyzed values are acceptable. When we have a target value of the Daylight Factor, we just have to determine the window area, transmittance of the glazing system, and indoor surface reflectance, then can achieve it with this simplified equation.

• 한국자동차공학회논문집
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• 제14권6호
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• pp.112-119
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• 2006

This paper is concerned with the light-weight design of a center-pillar assembly for the high-speed side impact of vehicle using advanced high strength steels(AHSS). Steel industries continuously promote the ULSAB-AVC project for applying AHSS to structural parts as an alternative way to improve the crashworthiness and the fuel efficiency because it has the superior strength compared to the conventional steel. In order to simulate deformation behavior of the center-pillar assembly, a simplified center-pillar model is developed and parts of that are subdivided employing tailor-welded blanks(TWB) in order to control the deformation shape of the center-pillar assembly. The thickness of each part which constitutes the simplified model is selected as a design parameter. Factorial design is carried out aiming at the application and configuration of AHSS to simplified side-impact analysis because it needs tremendous computing time to consider all combinations of parts. In optimization of the center-pillar, S-shaped deformation is targeted to guarantee the reduction of the injury level of a driver dummy in the crash test. The objective function is constructed so as to minimize the weight and lead to S-shape deformation mode. Optimization also includes the weight reduction comparing with the case using conventional steels. The result shows that the AHSS can be utilized effectively for minimization of the vehicle weight and induction of S-shaped deformation.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2011년도 제37회 추계학술대회논문집
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• pp.857-862
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• 2011

상세 화학반응 모델을 이용하여 3차원 터빈 배기가스 유동을 2차원 축대칭 유동으로 가정하여 해석하였다. GRI의 35 화학종 217 단계의 상세 모델과 메탄 반응만을 간략화 시킨 11화학종 15단계 모델을 적용하여 비교하였다. 메탄 화학반응을 적용한 결과 저부에서 터빈 배기가스의 이차 연소가 나타났고 터빈 배기 노즐이 없는 경우에 비하여 온도가 600K 정도 더 높게 나타났다. 실제 3차원 문제에서는 국부적인 온도는 더 높을 수 있음을 의미한다. 화학 반응 모델에 따라 저부에서의 연소 영역과 화학종 분포도 약간 다르지만 저부에서의 이차 연소는 모두 포착하였다. 다만 간략화된 모델인 경우 엔진 플룸의 구조에 약간의 영향을 주는 것을 관측된다.

• Steel and Composite Structures
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• 제24권4호
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• pp.425-439
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• 2017

As a thin-walled structure, local joint flexibility (LJF) in a tubular structure is prominent, and it may produce significant effect on the static performance for the overall structure. This study presents a simplified analytical model to analyze the static behavior for a steel tubular structure with LJF. The presented model simplifies a tubular structure into a frame model consisted of beam elements with considering the LJFs at the connections between any two elements. Theoretical equations of the simplified analytical model are deduced. Through comparison with 3-D finite element results of two typical planar tubular structures consisted of T- and Y-joints respectively, the presented method is proved to be accurate. Furthermore, the effect of LJF on the overall performance of the two tubular structures (including the deflection and the internal forces) is also investigated, and it is found from analyses of internal forces and deformation that a rigid connection assumption in a frame model by using beam elements in finite element analysis can provide unsafe and inaccurate estimation.

• 물과 미래
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• 제21권2호
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• pp.193-201
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• 1988

토양수분 특성함수의 고차 scanning 커브에 대한 간략한 모델을 개발하였다. Mualem의 개념적 이력모델을 고차 scanning 커브에 대하여 간략하게 변형시켰다. 즉, 고차 건조곡선에 대하여는 마지막 회향점을 연직하향으로 이동시켜 주습윤곡선과 만나는 점을 회향점으로 하는 일차건조곡선으로 간주하였다. 또, 고차 습윤곡선에 대하여는 마지막 회향점을 지나는 가상의 주건조곡선에서 출발하는 일차습윤곡선으로 간주하였다. 이 간략한 모델을 사용하여 이차 scanning 커브에 대하여 계산한 토양 함수량과 Mualem의 모델을 이용해서 구한 토양 함수량을 비교하였다. 그 결과 두 모델 사이의 절대오차는 비교적 작았으며, 간략한 모델이 Mualem 모델보다 고차 건조시에는 항상 낮게, 고차 습윤시에는 항상 높게 함수량을 추정하였다. 따라서 건조와 습윤을 반복하는 경우 오차는 서로 상쇄된다. 본 연구에서 개발된 간략한 모델이 고차 scanning 커브에서의 토양 함수량을 잘 추정하였으며 계산과정을 많이 감소시켰다.

• 한국농공학회논문집
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• 제64권1호
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• pp.27-37
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• 2022

This study established a water supply network based on the operation case of Mandae Reservoir in Yanggu-gun, Gangwon-do, to analyze the efficient distribution and management of agricultural water supplied from the reservoir to irrigation areas using the hydraulic analysis model SWMM. In order to construct a model to analyze the water canal network, network conditions needs to be simplified, and in particular, excessive detail or simplification of the irrigation area can lead to errors in the analysis results. Therefore, the effect of the water canal network model was analyzed by simulating the appropriate simplification process step by step. The results of simplifying the actual block shape of the analysis target area using SWMM showed that there was no significant difference in the results even if 7 lots were simplified to 2. Also, it was found that the construction and analysis of a simplified network model were reliable when the excess quantity was 2% or more compared to the required quantity for each case of analysis of the paddy field.

• Nuclear Engineering and Technology
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• 제31권3호
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• pp.257-266
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• 1999

A simplified statistical methodology is developed in order to both reduce over-conservatism of deterministic methodologies employed for PWR fuel rod internal pressure (RIP) calculation and simplify the complicated calculation procedure of the widely used statistical methodology which employs the response surface method and Monte Carlo simulation. The simplified statistical methodology employs the system moment method with a deterministic approach in determining the maximum variance of RIP The maximum RIP variance is determined with the square sum of each maximum value of a mean RIP value times a RIP sensitivity factor for all input variables considered. This approach makes this simplified statistical methodology much more efficient in the routine reload core design analysis since it eliminates the numerous calculations required for the power history-dependent RIP variance determination. This simplified statistical methodology is shown to be more conservative in generating RIP distribution than the widely used statistical methodology. Comparison of the significances of each input variable to RIP indicates that fission gas release model is the most significant input variable.

• 국제초고층학회논문집
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• 제1권4호
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• pp.247-254
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• 2012

In order to improve the seismic behaviors of traditional steel-concrete mixed structure, a novel steel concrete mixed structure consisting of steel frames braced with buckling restrained braces (BRBs) and a concrete tube is proposed. Based on several assumptions, the simplified mechanical model of the novel mixed structure is established, and the shear and bending stiffness formulas of the steel frames, BRBs and concrete tube are respectively introduced. The equilibrium differential equation of the novel mixed structure under horizontal load is developed based on the structural elastic theory. The simplified algorithms to determine the lateral displacement and internal forces of the novel mixed structure under the inverted-triangle distributed load, uniformly load and top-concentrated load are then obtained considering several boundary conditions and compatible deformation conditions. The effectiveness of the simplified algorithms is verified by FEM comparison.

• 대한토목학회논문집
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• 제31권2A호
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• pp.43-49
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• 2011

본 연구에서는 선교나 부선등에 실린 장비들과 같이 선박의 회전중심으로부터 이격된 선박구조와 교량의 상부구조가 충돌하는 경우의 충돌거동을 해석할 수 있도록 선박의 회전을 고려한 간이충돌모델을 개발하였다. 충돌모델은 선박과 교량의 질량과 강도 및 비선형성을 나타내도록 하였고, 모델의 비선형 운동방정식을 4차 Runge-Kutta방법을 이용하여 수치적으로 해석하였다. 현재 국내에서 운용되고 있는 부선의 제원을 선폭을 기준으로 표준화하고 작성된 충돌모델을 이용하여 각종 충돌조건이 교량의 충돌하중이 미치는 영향에 대한 매개변수연구를 수행하였다.

• 한국전산구조공학회논문집
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• 제16권4호
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• pp.377-386
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• 2003

본 논문에서는 단순화 다자유도 모델링 방법을 이용하여 유연한 지붕을 갖는 l/2 축소 단층 보강조적조 건물의 지진 거동을 분석하였다. 선형 및 비선형 해석에 의한 결과들은 l/2 축소모형 단층 건물의 진동대 실험결과와 비교ㆍ분석되었다. 정확한 면내 및 면외 강성과 강도를 산정할 적절한 방법이 없기 때문에 구조모델 보정방법을 적용하여 반복적인 비교 ·분석 과정에서 각 부재의 강성과 강도변화에 따른 민감도를 평가하였다. 보정된 구조물의 특성을 사용하여 구조 재해석을 수행하였으며, 지붕구조물의 유연성이 전체 건물의 동적 거동에 미치는 영향을 분석하였다. 유연한 지붕은 전단벽의 면외 강성과 강도에 많은 영향을 미치게 되며, 강체 지붕과는 확연히 구분되는 동적 거동을 보여주었다.