• Title, Summary, Keyword: FEM

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Temperature Distribution and Heat Transfer of Rectangular Cross-Section by the Finite Element Method (유한요소법(有限要素法)에 의(依)한 구형단면(矩形斷面)의 온도분포(溫度分布)와 열전도(熱傳導))

  • Yong, Ho-Taek;Seo, Jeong-Il;Im, Jang-Sun
    • Solar Energy
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    • v.1 no.1
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    • pp.23-29
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    • 1981
  • This paper studied the temperature distribution and heat transfer at a rectangular cross-section. Particularly, as we have known that FEM6, FEM10 can be able to divide FEM3 (25), FEM 3 (49) and we observed it with the details. The approximate solutions (FDM, FEM 3, FEM 3 (25), FEM 3 (49), FEM(6) were compared to the 2-dimensional exact solution. The results of this paper show that FEM 6 is the most accurate temperature profiles and heat transfer, furthermore mean values of the FEM 6 is more accurate than FEM 3(25) and FEM 3 (49).

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A Study on the Analysis of Trilateration Adjustment by Finite Element Method (FEM) (FEM에 의한 3 변측양의 해석에 관한 연구)

  • 이계학;장지원;정기현;김욱남
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.3 no.2
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    • pp.18-31
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    • 1985
  • The object of this study is to analize the trilateration adjustment by FEM. FEM is a numerical method for analysis dealing with problems of displacement and variation about the object. Since a plane trilateration net can be likend to a plan structural frame work in stress analysis, the technic of FEM can be used for trilateration adjustment Thus, this study applied FEM and Condition Equation Method to a trilateration adjustment, and investigated precision and characteristics of them.

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A Design of Attaching the Antenna to USPCS Band FEM (USPCS 대역 FEM 부착 안테나 설계)

  • Gang, Sung-Won;Cheon, Chang-Yul;Kim, Jun-Kyu
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.56 no.4
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    • pp.768-772
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    • 2007
  • Integration of RF front end module(FEM) into the antenna has been investigated in USPCS band (1.88GHz-1.99GHz). The FEM consists of input filter, power amplifier, coupler, power detector, bias switch and duplexer. The antenna was designed in planar inverted F antenna(PIFA) structure to implement it inside the handset. In order to avoid strong coupling between the antenna and FEM, a shielding ground layer was placed between them. The antenna size is 19mm by 10mm by 6mm under which FEM whose size is 8mm by 5mm by 1.5m locates. The antenna impedance was selected to match to FEM having better efficiency rather than gain since FEM has enough gain whose system spec is minimum of 20dB. The antenna patterns are shown with and without FEM.

On the Development of 3D Finite Element Method Package for CEMTool

  • Park, Jung-Hun;Ahn, Choon-Ki;Kwon, Wook-Hyun
    • 제어로봇시스템학회:학술대회논문집
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    • pp.2410-2413
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    • 2005
  • Finite element method (FEM) has been widely used as a useful numerical method that can analyze complex engineering problems in electro-magnetics, mechanics, and others. CEMTool, which is similar to MATLAB, is a command style design and analyzing package for scientific and technological algorithm and a matrix based computation language. In this paper, we present new 3D FEM package in CEMTool environment. In contrast to the existing CEMTool 2D FEM package and MATLAB PDE (Partial Differential Equation) Toolbox, our proposed 3D FEM package can deal with complex 3D models, not a cross-section of 3D models. In the pre-processor of 3D FEM package, a new 3D mesh generating algorithm can make information on 3D Delaunay tetrahedral mesh elements for analyses of 3D FEM problems. The solver of the 3D FEM package offers three methods for solving the linear algebraic matrix equation, i.e., Gauss-Jordan elimination solver, Band solver, and Skyline solver. The post-processor visualizes the results for 3D FEM problems such as the deformed position and the stress. Consequently, with our new 3D FEM toolbox, we can analyze more diverse engineering problems which the existing CEMTool 2D FEM package or MATLAB PDE Toolbox can not solve.

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An edge-based smoothed finite element method for adaptive analysis

  • Chen, L.;Zhang, J.;Zeng, K.Y.;Jiao, P.G.
    • Structural Engineering and Mechanics
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    • v.39 no.6
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    • pp.767-793
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    • 2011
  • An efficient edge-based smoothed finite element method (ES-FEM) has been recently developed for solving solid mechanics problems. The ES-FEM uses triangular elements that can be generated easily for complicated domains. In this paper, the complexity study of the ES-FEM based on triangular elements is conducted in detail, which confirms the ES-FEM produces higher computational efficiency compared to the FEM. Therefore, the ES-FEM offers an excellent platform for adaptive analysis, and this paper presents an efficient adaptive procedure based on the ES-FEM. A smoothing domain based energy (SDE) error estimate is first devised making use of the features of the ES-FEM. The present error estimate differs from the conventional approaches and evaluates error based on smoothing domains used in the ES-FEM. A local refinement technique based on the Delaunay algorithm is then implemented to achieve high efficiency in the mesh refinement. In this refinement technique, each node is assigned a scaling factor to control the local nodal density, and refinement of the neighborhood of a node is accomplished simply by adjusting its scaling factor. Intensive numerical studies, including an actual engineering problem of an automobile part, show that the proposed adaptive procedure is effective and efficient in producing solutions of desired accuracy.

A Study on the Analysis of Steady Magnetic Fields by the Coupling of FEM and BEM (FEM과 BEM의 혼합적용에 의한 정상자계의 해석에 관한 연구)

  • 임달호;김찬오
    • The Transactions of the Korean Institute of Electrical Engineers
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    • v.34 no.7
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    • pp.276-282
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    • 1985
  • This study is concerned with the analysis of two-dimensional steady magnetic fields by the coupling of FEM and BEM. FEM(Finite Element Method)is most widely used as a method of numerical analysis and BEM (Boundary Element Method)is a newest method for it. And the results from this coupling method are compared and discussed with those of FEM only. Consequently, it is shown that to obtain the same accuracy of results the coupling method requires less calculating time and dimension than the FEM.

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Effective Boundary Conditions for FEM Analysis of Composite Laminates (복합재료 적층판의 유한요소 해석을 위한 효율적 경계조건)

  • 김택현
    • Journal of The Korean Society of Manufacturing Technology Engineers
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    • v.7 no.3
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    • pp.92-98
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    • 1998
  • This paper presents three boundary techniques which are useful for FEM analysis of composite laminates: 1) a rotational symmetric boundary technique . 2) a quasi three-dimensional boundary technique and 3) a contact boundary technique. The use of the rotational symmetric boundary technique is possible for a smaller FEM model. With the use of the quasi three-dimensional boundary tecnique. quasi three dimensional analysis of composite laminates can be performed on the conventional 3-D FEM program These techniques can readily be adopted to FEM programs.

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Thermal Stress Analysis by Field Data Conversion between FDM and FEM (FDM과 FEM의 해석 데이터 변환에 의한 탄소성 열응력 해석)

  • Kwahk, S.Y.;Cho, C.D.
    • Journal of the Korean Society for Heat Treatment
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    • v.14 no.4
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    • pp.228-234
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    • 2001
  • The present study was an attempt for systematic data conversion between FDM and FEM in order to evaluate the thermal stress distribution during quenching process. It has been generally recognized that FDM is efficient in flow and temperature analysis and FEM in that of stress. But it induced difficulty and tedious work in analysis that one uses both FDM and FEM to take their advantages because of the discrepancy of nodes between analysis tools. So we proposed field data conversion procedure from FDM to FEM in 3-dimensional space, then applied this procedure to analysis of quenching process. The simulation procedure calculates the distributions of temperature and microstructure using FDM and microstructure evolution equations of diffusion and diffusionless transformation. FEM was used for predicting the distributions of thermal stress. The present numerical code includes coupled temperaturephase transformation kinetics and temperature-microstructure dependent material properties. Calculated results were compared with previous experimental data to verify the method, which showed good agreements.

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Prediction of Cutting Stress by 2D and 3D-FEM Analysis and Its Accuracy (2D-3D FEM 해석에 의한 절단응력의 해석 및 정도)

  • 장경호;이상형;이진형
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • pp.95-101
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    • 2001
  • Steel bridges, which have been damaged by load and corrosion, need repair or strengthening. In general, before the repair welding procedure, cutting procedure carry out. Therefore, the investigating of the behavior of stress generated by cutting is so important for safety of structure. Residual stress produced by gas cutting was analyzed using 2D and 3D thermal elasto-plastic FEM. According to the results, the magnitude of temperature was analyzed by 2D-FEM is smaller than that was analyzed using the 3D-FEM program at the start and end edge of flange. And the magnitude and distribution of residual stress of perpendicular to the cutting line was analyzed by the 2D-FEM program was similar to that was analyzed by the 3B-FEM program. Therefore, it is possible to predict of cutting stress by 2D and 3D FEM.

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Study of FEM with integrated antenna (안테나를 집적한 FEM에 대한 연구)

  • Kim Jun-Kyu;Kang Sung-Won;Cheon Chang-Yul
    • 한국정보통신설비학회:학술대회논문집
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    • pp.189-192
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    • 2006
  • 본 논문에서는 안테나와 미국 PCS대역(1.85GHz-1.99GHz) FEM(Front End Module)을 결합하여 하나의 패키지로 구현하는 것을 연구하였다. FEM의 크기를 고려하여 안테나의 크기를 작게 만들고 단말기에 내장하기 위해 PIFA(Planar Inverted F Antenna)형식의 안테나를 선택하였다. 안테나의 지지를 위해 비유전율 2의 캐리어를 사용하였고, 안테나와 FEM간의 상호 간섭을 막기 위해 도체로 차폐시켰다. 유한요소법(Finite Element Method)로 모의 실험을 하여 안테나를 설계하고 실제 제작하여 모의 실험결과와 비교하였다. 제작한 안테나를 FEM과 결합, 기판을 제작하여 FEM의 이득을 측정하였다.

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