• Proceedings of the Korean Fiber Society Conference
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• 2003.04a
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• pp.107-110
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• 2003

본 연구에서는 3차원 브레이딩 기계를 이용하여 제작된 6 layer의 3차원 원형 형태로 브레이드된 유리 섬유 강화 복합재료의 프리프레그를 이용하여 에폭시 수지를 모체로 하는 RTM(Resin Transfer Molding) 공정을 통해 직교 이방성 복합재료를 제작하였다. 또한 탄성한계 내에서의 구성방정식을 얻기 위해 unit cell 모델링을 통해 복합재료의 기하를 모사하고 method of cells 이론과 homogenization technique를 이용하여 복합재료의 구성방정식을 나타내는 수치해석 코드를 개발하였다. (중략)

• Nuclear Engineering and Technology
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• v.44 no.2
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• pp.207-224
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• 2012

This article discusses selects of some outstanding problems in nuclear reactor analysis, with proposed approaches thereto and numerical test results, as follows: i) multi-group approximation in the transport equation, ii) homogenization based on isolated single-assembly calculation, and iii) critical spectrum in Monte Carlo depletion.

• Journal of the Korea Institute of Military Science and Technology
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• v.8 no.2 s.21
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• pp.22-29
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• 2005

In this study we performed topology optimization and size optimization about support structure of pressure container which is installed in a Common Bed. The optimization study shows that structure weight optimization results can be applied to navy ship. The topology optimization is performed by static load, homogenization and optimality criteria method and size optimization is performed by SOL200 of NASTRAN.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2017.05a
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• pp.35-36
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• 2017

• Proceedings of the PSK Conference
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• 2002.10a
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• pp.425.2-425.2
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• 2002

The purpose of this study was to prepare thermo-sensitive solid-lipid nanoparticles (SLNs) with a lipid melted at human body temperature and to evaluate physicochemical properties of SLNs containing retinol. anti-wrinkle agent. as a model drug. SLNs were prepared using a high pressure homogenizing method. The SLNs were composed of retinol as a model drug. thermo-sensitive lipid (DS-CBS) as a lipid core. and egg phosphatidylcholine and Tween 80 as surfactants. Manufacturing variables such as homogenization pressure. (omitted)

• Advances in biomechanics and applications
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• v.1 no.2
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• pp.111-126
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• 2014

The microarchitecture of trabecular bone plays a significant role in mechanical strength due to its load-bearing capability. However, the complexity of trabecular microarchitecture hinders the evaluation of its morphological characteristics. We therefore propose a new classification method based on static multiscale theory and dynamic finite element method (FEM) analysis to visualize a three-dimensional (3D) trabecular network for investigating the influence of trabecular microarchitecture on load-bearing capability. This method is applied to human vertebral trabecular bone images obtained by micro-computed tomography (micro-CT) through which primary trabecular bone is successfully visualized and extracted from a highly complicated microarchitecture. The morphological features were then analyzed by viewing the percolation of load pathways in the primary trabecular bone by using the stress wave propagation method analyzed under impact loading. We demonstrate that the present method is effective for describing the morphology of trabecular bone and has the potential for morphometric measurement applications.

• Journal of the Korean Society for Precision Engineering
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• v.13 no.7
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• pp.66-77
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• 1996

Optimal topology design is to search the optimal configuration of a structure which can be used as a shape at the conceptual design stage. Our objective is to maximize the stiffness of the structures and ribs under a material usage constraintl. The density of each finite element is the design variable and its relationship with Young's modulus is expressed by quadratic form. The configuration is represented by the entire density distribution, the structural analysis is performed by finite element method and the optimiza- tion is performed by Feasible Direction Method. Feasible Direction Method can handle various problems simultaneously, that is, mult-objectives and multi-constraints. Total computation time can be reduced by the quadratic relationship between the density and the material property and fewer design variables than Homogenization Method. Toplogy optimization technique developed in this research is applied to design the shapes of the ribs.

• Journal of Mechanical Science and Technology
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• v.14 no.3
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• pp.306-313
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• 2000

The homogenization method and the density function method are common approaches to evaluate the equivalent material properties for design cells composed of matter and void. In this research, using a new topology optimization method based on the homogenized material with a penalty factor and the chessboard prevention strategy, we obtain the optimal layout of a structure for the natural frequency of a designated mode. The volume fraction of nodes of each finite element is chosen as the design variable and a total material usage constraint is imposed. In this paper, the subspace method is used to evaluate the eigenvalue and its corresponding eigenvector of the structure for the designated mode and the recursive quadratic programming algorithm, PLBA algorithm, is used to solve the topology optimization problem.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1994.10a
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• pp.852-859
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• 1994

Optmal topology design is to search the optimal layout of the structure which can be used fot the shape of the conceptual design stage. Our objective is to maximize the stiffness of the structure under a material usage constraint. The density of each finite element is the design variable and its relationship with Young's modulus is expressed by quadratic form. The shape is represented by the entire density distribution, the structural analysis is performed by finite element method and the optimization is achieved by feasible direction method. Unlike optimality criteria method,feasible direction method can handle various problems simultaneously, that is, multi- objectives and multi-constraints. Total optimization time can be reduced by the approximation of the material property and fewer design variables than homogenization method. Topology optimization is applied to design the shape of ribs.

• Proceedings of the Safety Management and Science Conference
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• 2011.11a
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• pp.67-74
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• 2011

In this study numerical analysis was performed to evaluate the safety of Built-in Timbering Roof Type Tunnelling Method(BTR) which is one of non-opening tunnel construction methods. For the upgrading of analytical precision was applied the discretion method which can separately model reinforcing elements of BTR and the homogeneity analysis considering the area ratio of elements was performed to compare both results. Comparing the displacement in this study with that of the homogeneity method, the efficiency of the discretion method was verified.