• Title, Summary, Keyword: FEM analysis

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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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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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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 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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FEM Modeling Automation of Machine Tools Structure (공작기계 구조물의 전산 모델링 자동화)

  • Lee, Chan-Hong;Ha, Tae-Ho;Lee, Jae-Hak
    • Journal of the Korean Society for Precision Engineering
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    • v.29 no.10
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    • pp.1043-1049
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    • 2012
  • The FEM analysis of machine tools is the general analysis process to evaluate machine performance in the industry for a long time. Despite advances in FEM software, because of difficult simplicity of CAD drawing, little experience of joints stiffness modeling and troublesome manual contact area divide for bindings, the industry designers think the FEM analysis is still an area of FEM analysis expert. In this paper, the automation of modeling process with simplicity of drawing, modeling of joints and contact area divide is aimed at easy FEM analysis to enlarge utilization of a virtual machine tools. In order to verify the effects of modeling automation, a slant bed type model with tilting table is analyzed. The results show FEM modeling automation method only needed 45 minutes to complete the whole modeling process, while manual modeling method requires almost one month with 8200 calculations for coordinate transformations and stiffness data input.

A Study on a Composite Laminate Pull-through Joint

  • Kwon, Jeong-Sik;Kim, Jin-Sung;Seo, Bum-Kyung;Lee, Soo-Yong
    • International Journal of Aeronautical and Space Sciences
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    • v.18 no.1
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    • pp.63-69
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    • 2017
  • In this paper, composite laminate pull-through resistance was analyzed using the FEM method and compared with test results. 2D and 3D simplified FEM models, a nonlinear analysis, and a progressive failure analysis utilizing three composite laminate failure theories Maximum Stress, Maximum Strain, and Tsai-Wu were used to predict the FEM results with the test results. The load and boundary conditions of the test were applied to the FEM to simulate the test. A composite laminate pull-through test (ASTM D7332 Proc. B) was designed with a special fixture to collect more precise data. The test results were compared with the FEM analysis results.

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.

Forced Vibration Analysis of Plate Structures Using Finite Element-Transfer Stiffness Coefficient Method (유한요소-전달강성계수법을 이용한 평판 구조물의 강제진동해석)

  • 최명수
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.13 no.2
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    • pp.99-107
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    • 2003
  • The finite element method(FEM) is the most widely used and powerful method for structural analysis. In general, in order to analyze complex and large structures, we have used the FEM. However, it is necessary to use a large amount of computer memory and computation time for solving accurately by the FEM the dynamic problem of a system with many degree-of-freedom, because the FEM has to deal with very large matrices in this case. Therefore, it was very difficult to analyze the vibration for plate structures with a large number of degrees of freedom by the FEM on a personal computer. For overcoming this disadvantage of the FEM without the loss of the accuracy, the finite element-transfer stiffness coefficient method(FE-TSCM) was developed. The concept of the FE-TSCM is based on the combination of modeling technique in the FEM and the transfer technique in the transfer stiffness coefficient method(TSCM). The merit of the FE-TSCM is to take the advantages of both methods, that is, the convenience of the modeling in the FEM and the computation efficiency of the TSCM. In this paper, the forced vibration analysis algorithm of plate structures is formulated by the FE-TSCM. In order to illustrate the accuracy and the efficiency of the FE-TSCM, results of frequency response analysis for a rectangular plate, which was adopted as a computational model, were compared with those by the modal analysis method and the direct analysis method which are based on the FEM.

Study on Torque Analysis of Micro-Electromagnetic Clutch by Using FEM (FEM을 이용한 Micro-Electromagnetic Clutch 토크해석)

  • Piao Changhao;Cho Chongdu;Kim Myunggu;Pan Qiang
    • The Transactions of the Korean Institute of Electrical Engineers B
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    • v.54 no.2
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    • pp.60-65
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    • 2005
  • This study tries to analyzes the static friction torque that generated in a micro-electromagnetic clutch by using FEM. For the purpose of design change and optimization of the micro-electromagnetic clutch, the static friction torque prediction is very important. We construct the axi symmetric FEM model for analyze the static friction torque and the real material properties are substituted to the FEM model. For a test, predicted static friction torque is compared with experimental one to discuss the rationality of torque analysis process. The analytical result agrees well to experimental data. explaining the validity of the mathematical process and FEM model.

Repair LCC Evaluation of RC Structures through the FEM Analysis of Chloride Ion Penetration (염소이온 침투 FEM 해석을 통한 RC구조물의 보수 LCC 평가)

  • Lee, Han-Seung
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.10 no.1
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    • pp.223-230
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    • 2006
  • In this paper the method for repair LCC evaluation of reinforced concrete structures deteriorated by chloride attack was constructed. Also, the FEM analysis for chloride ion penetration into concrete was conducted to evaluate the repair LCC which was decided by the number of repair times including early stages of construction and repair construction during the service life of structures. As a result, the number of repair times is obtained from the comparing the concentration of the chloride ion in a rebar position, and the critical chloride ion concentration of rebar corrosion through the FEM analysis considering the kind of repair materials and methods. Also, the repair LCC could be calculated by the number of repair times during the service life of structures.