• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.36 no.1
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• pp.86-91
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• 2008

An integrated multidisciplinary analysis and design system plays a critical role in the preliminary design of an aircraft. In this work a system based on the CATIA is developed for multidisciplinary computational design; aerodynamics, elasticity, and radar frequency stealth. Common data base of geometry and rectangular grids is generated and used for aerodynamic and structural analysis, while derivative triangular grids are generated for the RCS calculation. The panel method (PANAIR), FEM (NASTRAN), and PO technique are used for aerodynamic, structural, and RF stealth computations, respectively, and several additional algorithms are developed for the effective communication of the common data.

• Proceedings of the KAIS Fall Conference
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• 2004.06a
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• pp.75-77
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• 2004

본 논문에서는 레그 익스텐션 기구의 안정성을 평가하기 위하여 3차원 유한요소 해석 코드인 ANSYS를 활용하여 구조해석을 실시하였다. 레그 익스텐션 기구를 제작함에 있어서 기존의 기구를 보완하고 운동효과의 향상, 안정성을 고려하여 설계하였다. 또한 레그 익스텐션 기구의 회전봉의 각도를 $0^{\circ}\~360^{\circ}$까지 회전가능하게 설계하여 운동하는 사람의 운동 강도를 조절할 수 있는 새로운 기구를 설계하였다.

• Transactions of the Korean Society of Mechanical Engineers
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• v.13 no.5
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• pp.820-830
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• 1989

The tire inflation and contact problem has been solved by a finite element method. The finite element formulation is derived from the equilibrium equations by the principle of virtual work in the form of an updated Lagrangian formulation for incremental analysis. Then, a contact formulation is added to the finite element formulation to calculate stress state of tire in contact with flat rigid road under the load due to the self-weight of a vehicle. In the finite element analysis, equations of effective material properties are introduced to analyze a plane strain model of the shell-like tire by considering the bending effect of reinforced steel cords. The proposed equations of effective material properties produced stress concentration around the edge of belt layers, which does not appear when other well-known equations of material properties are adopted. The result from the above algorithm demonstrates the validity of the formulation and the proposed equations for the effective elastic constants. The result fully interprets the cause of separation between belt layers by showing the stress concentration.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.24 no.3
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• pp.329-335
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• 2011

The finite element method (FEM) has been used for various fields like mathematics and engineering. However, the FEM has a difficulty in describing the geometric shape exactly due to its property of piecewise linear discretization. Recently, however, a so-called isogeometric analysis method that uses the non-uniform rational B-spline(NURBS) basis function has been developed. The NURBS can be used to describe the geometry exactly and play a role of basis functions for the response analysis. Nevertheless, constructing the NURBS basis functions in analysis is as costly as a meshing process in the FEM. Since the isogeometric method shares geometric data with CAD, it is possible to intactly import the model data from commercial CAD tools. In this paper, we use the Rhinoceros 3D software to create CAD models and export in the form of STEP file. The information of knot vectors and control points in the NURBS is utilized in the isogeometric analysis. Through some numerical examples, the accuracy of isogeometric method is compared with that of FEM. Also, the efficiency of the isogeometric method that includes the CAD and CAE in a unified framework is verified.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.15 no.3
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• pp.471-480
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• 2002

In this paper, the thermal stress analysis of spent nuclear fuel disposal canister in a deep repository at 500 m underground is carried out for the basic design of the canister. Since the nuclear fuel disposal usually emits much heat, a long term safe repository at a deep bedrock is used. Under this situation, the canister experiences the thermal load due to the heat generation of spent nuclear fuels in the basket. Hence, in this paper the thermal stress analysis is executed using the finite element method. The finite clement code Eot the analysis Is not written directly, but a commercial code, NISA, is used because of the complexity of the structure and the large number of elements required for the analysis. The analysis result shows that even though the thermal stress is added to the stress generated by the hydrostatic underground water pressure and the swelling pressure of the bentonite buffer, the total stress is still smaller than the yield stress of the cast iron. Hence, the canister is still structurally safe when the thermal loads we included in the external loads applied on the canister.

• Journal of the Korea Institute of Building Construction
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• v.17 no.1
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• pp.63-72
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• 2017

This research investigated the effect of solar radiation on the temperature distribution in concrete mat foundation. Zhang and Huang Model was utilized to estimate solar radiation heat at a given date and time. A one-dimensional finite element formula was derived with the fundamental laws of heat transfer and Galerkin method. Based on the formula, a one dimensional finite element analysis code was developed using MATLAB. Hydration heat analysis of mat foundation were conducted using the developed code. It was found that the solar radiation reduced the maximum temperature difference in mat foundation, and this temperature difference reduction was more prominent in case of summer season cast, a higher initial concrete temperature, and a thicker mat foundation depth. The research recommended that the solar radiation should be considered in hydration heat analysis of concrete mat foundation so as not to overestimate the maximum temperature difference in mat foundation.

• Proceedings of the KAIS Fall Conference
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• 2011.05b
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• pp.947-950
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• 2011

기존의 밸브 수압측정기는 압력조절을 수동으로 조절함으로서 정확한 압력측정을 할 수 없는 불편함이 있었다. 이를 밸브의 수압측정 시 압력조절센서를 이용하여 압력조절을 안전하고 정확하게 개선한다. 또한 3차원 유한요소 코드인 ANSYS를 활용하여 설계된 수압측정기에 대하여 구조해석을 수행하여 수압측정기 내부압력에 따른 내부누수, 응력, 변형률, 총변형량 등을 구하였다.

• Journal of the Korean Society for Precision Engineering
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• v.24 no.2 s.191
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• pp.19-24
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• 2007

• Proceedings of the KSME Conference
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• 2001.06c
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• pp.572-579
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• 2001

Recent industrial requirements for highly precise shape processing have brought the electric discharge machining (EDM) in great need. High precision in EDM is primarily achieved by high performance controllers. However there exists inherent precision loss due to structural deformation. On this background, we study structural deformation characteristics of wire cut EDM via finite element (FE) analysis and axiomatic design. Two different wire cut EDMs are selected as analysis models. 3D CAD package I-Deas is first used to construct FE models of wire cut EDMs, and then ABAQUS FE code is used for following structural analysis. Pertinency of FE mesh refinement is discussed in terms of ${\eta}-factor$. It is shown that performance accuracy of EDM depends strongly on the structural characteristics. Some design enhancements are suggested in an axiomatic design point of view. Finally we provide weight and temperature induced displacement discrepancies between wire end points as position functions of each subframe.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.3
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• pp.317-323
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• 2011

We use the finite element method to analyze the seismic design of a liquid storage tank for a polar crane at a nuclear power plant. We obtained the natural frequency and vibration modes by modal analysis, and we evaluated the seismic stability by response spectrum analysis. Furthermore, the seismic analysis of the tank was accomplished by analyzing not only the forces applied to the wall by the sloshing of the liquid, but also the safe-shutdown earthquake condition for the tank. We propose a seismic-design process and a seismic-analysis method for liquid storage tanks based on the commercial finite element analysis program, ANSYS.