• Title, Summary, Keyword: finite element method (FEM)

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Iterative coupling of precise integration FEM and TD-BEM for elastodynamic analysis

  • Lei, Weidong;Liu, Chun;Qin, Xiaofei;Chen, Rui
    • Structural Engineering and Mechanics
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    • v.67 no.4
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    • pp.317-326
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    • 2018
  • The iterative decomposition coupling formulation of the precise integration finite element method (FEM) and the time domain boundary element method (TD-BEM) is presented for elstodynamic problems. In the formulation, the FEM node and the BEM node are not required to be coincident on the common interface between FEM and BEM sub-domains, therefore, the FEM and BEM are independently discretized. The force and displacement converting matrices are used to transfer data between FEM and BEM nodes on the common interface between the FEM and BEM sub-domains, to renew the nodal variables in the process of the iterations for the un-coincident FEM node and BEM node. The iterative coupling formulation for elastodynamics in current paper is of high modeling accuracy, due to the semi-analytical solution incorporated in the precise integration finite element method. The decomposition coupling formulation for elastodynamics is verified by examples of a cantilever bar under a Heaviside-type force and a harmonic load.

Surface Temperature in Sliding Systems Using the FFT Finite Element Analysis (FFT-FEM을 이용한 윤활 기구에서 표면온도에 관한 연구)

  • 조종두;안수익
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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    • pp.73-79
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    • 1999
  • Finite element equations by using fast Fourier transformation were formulated for studying temperatures resulting from frictional heating in sliding systems. The equations include the effect of velocity of moving components. The program developed by using FFT-FEM that combines Fourier transform techniques and the finite element method, was applied to the sliding bearing system. Numerical prediction obtained by FFT-FEM was in an excellent agreement of experimental temperature measurements.

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Surface Temperature in Sliding Systems Using the En Finite Element Analysis (FFT-FEM을 이용한 윤활 기구에서 표면온도에 관한 연구)

  • 조종두;안수익
    • Tribology and Lubricants
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    • v.16 no.3
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    • pp.218-222
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    • 2000
  • Finite element equations by using fast Fourier transformation were formulated for studying temperatures resulting from frictional heating in sliding systems. The equations include the effect of velocity of moving components. The program developed by using FFT-FEM that combines Fourier transform techniques and the finite element method, was applied to the sliding bearing system. Numerical prediction obtained by FFT-FEM was in an excellent agreement of experimental temperature measurements.

Comparative study between Finite Element Method and Limit Equilibrium Method on Slope Stability Analysis (사면안정해석에 있어서의 유한요소법과 한계평형법의 비교)

  • 이동엽;유충식
    • Proceedings of the Korean Geotechical Society Conference
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    • pp.483-490
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    • 2002
  • This paper presents the results of a comparative study between FEM and LEM on slope stability analysis. For validation, factors of safety were compared between FEM and LEM. The results from the two methods were in good agreement suggesting that the FEM with the shear strength reduction method can be effectively used on slope stability analyses. A series of analysis were then performed using the FEM for various constitutive laws, slope angles, flow rules, and the finite element discretizations. Among the findings, the finite element method in conjunction with the shear strength reduction method can provide reasonable results in terms of factor of safety. Also revealed is that the results of FEM can be significantly affected by the way in which the type of constitutive law and flow rule are selected.

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Free Vibration Analysis of Rectangular Plates by the Combined Transfer Stiffness Coefficient Method and Finite Element Method (전달강성계수법과 유한요소법의 조합에 의한 사각평판의 자유진동해석)

  • 문덕홍;최명수
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.353-358
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    • 1998
  • In general, we have used the finite element method(FEM) to find natural frequencies of plates. In this method, however, it is necessary to use a large amount of computer memory and computation time because the FEM requires many degrees of freedom for finding natural frequencies of plates correctly. Therefore it was very difficult to analyze the free vibration of plates correctly on personal computer. For overcoming this disadvantage of the FEM, the authors have developed the finite element-transfer stiffness coefficient method(FE-TSCM) which is based on the concept of modeling techniques in the FEM and the transfer of the stiffness coefficient in the transfer stiffness coefficient method. In this paper, we formulate free vibration analysis algorithm of rectangular plates using the FE-TSCM. Some numerical examples of rectangular plates are proposed, and their results and computation times obtained by the FE-TSCM are compared with those by the FEM and the finite element-transfer matrix method in order to demonstrate the accuracy and efficiency of the FE-TSCM.

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A Study on the comparison of FEM and FEM for Backward Impact Extrusion Process (후방 충격압출 성형 공정의 FVM과 FEM의 적용성에 관한 연구)

  • 정상원;조규종;김성훈
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • pp.1565-1568
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    • 2003
  • The backward extrusion process is one of the commonly used metal forming processes. In this paper. a battery case which has the rectangular section, is analyzed using a 3D metal forming package(MSC.Superforge). This pacakge uses the finite volume analysis method. It is shown that the MSC.Superforge package using finite volume method provides result very close to those obtained from a finite element analysis package(MSC.Superform). However, the simulation time using the finite volume method was almost 10 % of the simulation time consumed by the other package using finite element method. Moreover, the finite volume method used in MSC.Superforge can eliminate the remeshing problems that make the simulating a metal forming process with severe deformation, such as the extrusion process, so difficult.

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Static Analysis of Three Dimensional Solid Structure by Finite Element-Transfer Stiffness Coefficent Method Introducing Hexahedral Element (육면체 요소를 도입한 유한요소-전달강성계수법에 의한 3차원 고체 구조물의 정적 해석)

  • Choi, Myung-Soo;Moon, Deok-Hong
    • Journal of the Korea Society For Power System Engineering
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    • v.16 no.1
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    • pp.78-83
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    • 2012
  • The authors suggest the algorithm for the static analysis of a three dimensional solid structure by using the finite element-transfer stiffness coefficient method (FE-TSCM) and the hexahedral element of the finite element method (FEM). MATLAB codes were made by both FE-TSCM and FEM for the static analysis of three dimensional solid structure. They were applied to the static analyses of a very thick plate structure and a three dimensional solid structure. In this paper, as we compare the results of FE-TSCM with those of FEM, we confirm that FE-TSCM introducing the hexahedral element for the static analysis of a three dimensional solid structure is very effective from the viewpoint of the computational accuracy, speed, and storage.

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.

Multiscale analysis using a coupled discrete/finite element model

  • Rojek, Jerzy;Onate, Eugenio
    • Interaction and multiscale mechanics
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    • v.1 no.1
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    • pp.1-31
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    • 2008
  • The present paper presents multiscale modelling via coupling of the discrete and finite element methods. Theoretical formulation of the discrete element method using spherical or cylindrical particles has been briefly reviewed. Basic equations of the finite element method using the explicit time integration have been given. The micr-macro transition for the discrete element method has been discussed. Theoretical formulations for macroscopic stress and strain tensors have been given. Determination of macroscopic constitutive properties using dimensionless micro-macro relationships has been proposed. The formulation of the multiscale DEM/FEM model employing the DEM and FEM in different subdomains of the same body has been presented. The coupling allows the use of partially overlapping DEM and FEM subdomains. The overlap zone in the two coupling algorithms is introduced in order to provide a smooth transition from one discretization method to the other. Coupling between the DEM and FEM subdomains is provided by additional kinematic constraints imposed by means of either the Lagrange multipliers or penalty function method. The coupled DEM/FEM formulation has been implemented in the authors' own numerical program. Good performance of the numerical algorithms has been demonstrated in a number of examples.

Stress Analysis of Axisymmetric Cylindrical Shell (축대칭 원통형 셸의 응력해석)

  • Choi, M.S.;Yeo, D.J.
    • Journal of the Korea Society For Power System Engineering
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    • v.16 no.6
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    • pp.45-51
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    • 2012
  • In this paper, the algorithm for the static analysis of an axisymmetric cylindrical shell by using the finite element-transfer stiffness coefficient method (FE-TSCM) is suggested. TE-TSCM combining both the modeling procedure of the finite element method (FEM) and the transfer procedure of the transfer stiffness coefficient method (TSCM) has the advantages of FEM and TSCM. After computational programs are made by both FE-TSCM and FEM for the stress analysis of the axisymmetric cylindrical shell, we compare the numerical results by FE-TSCM with those of FEM for two computational models in order to confirm the trust of FE-TSCM.