• Aerospace Engineering and Technology
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• v.4 no.1
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• pp.45-48
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• 2005

Study on the thermal pointing error analysis for optical bench was performed in this paper. Spacecraft FEM is necessary to conduct thermal pointing error analysis for optical bench. But generally during the preliminary design, exact spacecraft FEM does not exist. So the analysis method to predict thermal pointing error of spacecraft is necessary without exact spacecraft FEM. In this study, these analysis techniques are described.

• Journal of Advanced Marine Engineering and Technology
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• v.36 no.6
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• pp.794-801
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• 2012

Finite Element Method is a strong tool to analyse static and dynamic problem of a structure. FEM is a good method for static problem, but for dynamic problem there are some differences between real phenomena and analyzed phenomena. Therefore some modifications are needed to identify two results. In this paper authors propose a genetic algorithm method 1) to adjust dimensions of plate for identifying natural frequencies, 2) to fit amplitude of FEM Frequency Response Function(FRF) onto it of real FRF. Analysis by raw FEM data gave questions if the results were for the same object. By only adjusting Young's modulus much better accordances were obtained, but limitation existed still. Very good agreements were achieved by shape modification and damping coefficient identification.

• International Journal of Highway Engineering
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• v.10 no.3
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• pp.129-138
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• 2008

The finite element method(FEM) was one of tools used to solve problem of previous Concrete Pavement and was applied to Korea Pavement Research Program Study. This study used the ABAQUS and the fortran analysis program to calculate the critical stress on jointed concrete pavement and compared and analyzed the results by using neural networks and linear regression model. In that case, which are not enough analysises by using FEM programs though many input variables, when the results of FEM with NN and linear regression models are compared, there are some differences. The other cases, which are reduced input variables and a lot of analysises each of them, results of Neural Networks(NN) and linear regression models are simulated to them of FEM. But, the result of NN is more exact than them of linear regression at the (0,0), (1,1). On the results of this study, it is suggested that the calculation of stress using NN is more compatible to Korea Pavement Research Program Study.

• Journal of the Korean Institute of Gas
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• v.7 no.3 s.20
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• pp.58-64
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• 2003

This paper presents design safety analysis of pressure vessels. The gas pressure and thermal loads are applied to the pressure vessel simultaneously. In this study, ASME Sec. VIII Div. 2 code was accepted for the safety design of high-pressure vessel. And this result was analyzed using a coupled thermal-mechanical FEM analysis technique. The FEM computed result shows that ASME design code may not guarantee for combined loads of high gas pressure and thermal loads. And solid pressure vessel may be safe compared to other pressure vessels with supporting rings round the cylinder body.

• Journal of Advanced Marine Engineering and Technology
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• v.36 no.4
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• pp.467-475
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• 2012

In this paper, a technical method of reducing torque load of exoskeleton device, with using of a gravity compensator based on a torsion bar, for human leg joints, is proposed. Design and structure analyses and also performance test were performed to estimate and to measure the characteristics of the torsion bar. On the basis of design and structure analysis, a new light and compact exoskeleton device has been developed. For the purpose of lightening and optimizing thickness of the links, FEM analysis has been performed.

• Journal of Korean Tunnelling and Underground Space Association
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• v.3 no.4
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• pp.3-15
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• 2001

Generally, it has been noted that underground structures have a consistent record of suffering much less damage than surface facilities during earthquakes; but it is still necessary to illustrate the dynamic response of tunnel structures subject to earthquake loadings and to provide the appropriate method for the seismic analysis of underground tunnel structures since many types of underground structures have been and will be constructed in countries situated within seismic zones. In this study, first, seismic analyses for underground tunnel structures are performed by using quasistatic analysis method and dynamic analysis method. Second, seismic analyses in tunnel portals are performed by using above methods. The results of seismic analyses for the tunnel structure show that the tunnel structure conforms to ground deformation and that seismic design by using the quasi-static analysis method is more conservative than that by using the dynamic analysis. The results of the dynamic FEM analysis for the tunnel structure show that the simplified 2-D FEM analysis using a sine wave rather than the 3-D FEM analysis can be adopted for seismic analysis. Finally, the results of the dynamic FEM analysis in tunnel portals show that the force acting on the lining is largest near to the tunnel portal when an earthquake wave propagates parallel to tunnel axis.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2015.05a
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• pp.55-56
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• 2015

This study is corroborated as a fundamental resource to develop structural lightweight paste containing silica fume as a part of cement. Paste using foaming agent is generated much foam and decreased density of paste. This study is measured at 0.8% of foaming agent dosage but over 0.8% of foaming agent dosage raise density of paste because of interconnection with foam. Also, FEM analysis using SEM image is confirmed correspondence of between Elastic modulus of experiment and FEM analysis.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.750-751
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• 2008

본 논문은 컨버터용 변압기의 여자전류 해석을 통해 DC 성분 유입시 자속밀도-여자전류 곡선 그래프를 도출하여 철심포화 여부를 확인하며, 철심 공극에 의해 발생되는 누설자속(Leakage Flux)으로 인한 철구조물(Lock Plate)의 와전류 손실을 계산하였다. 변압기 해석을 위해 상용 해석 소프트웨어인 Maxwell 3D를 이용하였고, 철심의 비선형성을 고려하여 해석하였다.

• Proceedings of the KIEE Conference
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• 2003.10b
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• pp.107-109
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• 2003

본 논문은 전력기기 중 저압 재폐로(Recloser) 차단기에 대한 FEM을 이용한 조작부 구동메커니즘의 동작특성에 대해 연구하였다. 중 저압 차단기는 크게 차단부와 조작부로 분리할 수 있는데 조작부메커니즘은 동작특성의 영향을 많이 받기 때문에 차단동작특성이 좋고 신뢰성 및 반복성이 우수한 영구자석형 마그네틱 액추에이터를 사용하였다. 그리고, 정확한 동작 특성 해석을 위해 물질의 비선형 특성을 고려하였고, 외부회로와 결합하여 2-D FEM을 통한 전자계 해석을 하였다. 또한, 실험을 통한 최종적인 기계적인 힘과 FEM으로 해석한 액추에이터의 힘을 비교 검증하였다.

• Proceedings of the KIEE Conference
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• 2006.07d
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• pp.2109-2110
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• 2006

유한요소법은 전자기, 기계, 또는 다른 공학 분야에서 다루는 풀기 어려운 복잡한 문제들을 해석하는데 널리 사용되고 있는 수치해석기법이다. CEMTool은 MATLAB과 유사한 과학기술 범용 패키지로서, 간편한 명령어 방식의 문법과 블록 다이어그램 설계, 이공학 전반의 함수 등의 다양한 기능들을 제공한다. 본 논문에서는 범용 공학 소프트웨어인 CEMTool 환경에서 실행되는 GUI 3D FEM 패키지에 대해 기술한다. FEM 해석의 일반적 단계인 전처리, 솔버, 후처리 단계별로 나누어 각 단계의 구조와 특징 등을 기존의 CEMTool 2D FEM 패키지, MATLAB PDE Toolbox, FEMLAB2.2와 비교하여 자세히 살펴보기로 한다.