• Title/Summary/Keyword: Finite Value Method

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Development of a meshless finite mixture (MFM) method

  • Cheng, J.Q.;Lee, H.P.;Li, Hua
    • Structural Engineering and Mechanics
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    • v.17 no.5
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    • pp.671-690
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    • 2004
  • A meshless method with novel variation of point collocation by finite mixture approximation is developed in this paper, termed the meshless finite mixture (MFM) method. It is based on the finite mixture theorem and consists of two or more existing meshless techniques for exploitation of their respective merits for the numerical solution of partial differential boundary value (PDBV) problems. In this representation, the classical reproducing kernel particle and differential quadrature techniques are mixed in a point collocation framework. The least-square method is used to optimize the value of the weight coefficient to construct the final finite mixture approximation with higher accuracy and numerical stability. In order to validate the developed MFM method, several one- and two-dimensional PDBV problems are studied with different mixed boundary conditions. From the numerical results, it is observed that the optimized MFM weight coefficient can improve significantly the numerical stability and accuracy of the newly developed MFM method for the various PDBV problems.

FUNCTIONAL ITERATIVE METHODS FOR SOLVING TWO-POINT BOUNDARY VALUE PROBLEMS

  • Lim, Hyo Jin;Kim, Kyoum Sun;Yun, Jae Heon
    • Journal of applied mathematics & informatics
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    • v.31 no.5_6
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    • pp.733-745
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    • 2013
  • In this paper, we first propose a new technique of the functional iterative methods VIM (Variational iteration method) and NHPM (New homotopy perturbation method) for solving two-point boundary value problems, and then we compare their numerical results with those of the finite difference method (FDM).

A FINITE DIFFERENCE APPROXIMATION OF A SINGULAR BOUNDARY VALUE PROBLEM

  • Lee, H.Y.;Ohm, M.R.;Shin, J.Y.
    • Bulletin of the Korean Mathematical Society
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    • v.35 no.3
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    • pp.473-484
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    • 1998
  • We consider a finite difference approximation to a singular boundary value problem arising in the study of a nonlinear circular membrane under normal pressure. It is proved that the rate of convergence is $O(h^2)$. To obtain the solution of the finite difference equation, an iterative scheme converging monotonically to the solution of the finite difference equation is introduced. And the numerical experiment of this method is given.

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CUBIC SPLINE METHOD FOR SOLVING TWO-POINT BOUNDARY-VALUE PROBLEMS

  • Al Said, Eisa-A.
    • Journal of applied mathematics & informatics
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    • v.5 no.3
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    • pp.759-770
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    • 1998
  • In this paper we use uniform cubic spline polynomials to derive some new consistency relations. These relations are then used to develop a numerical method for computing smooth approxi-mations to the solution and its first second as well as third derivatives for a second order boundary value problem. The proesent method out-performs other collocations finite-difference and splines methods of the same order. numerical illustratiosn are provided to demonstrate the practical use of our method.

REDUCTION METHOD APPLIED TO THE NONLINEAR BIHARMONIC PROBLEM

  • Jung, Tacksun;Choi, Q-Heung
    • Korean Journal of Mathematics
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    • v.18 no.1
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    • pp.87-96
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    • 2010
  • We consider the semilinear biharmonic equation with Dirichlet boundary condition. We give a theorem that there exist at least three nontrivial solutions for the semilinear biharmonic boundary value problem. We show this result by using the critical point theory, the finite dimensional reduction method and the shape of the graph of the corresponding functional on the finite reduction subspace.

THOMAS ALGORITHMS FOR SYSTEMS OF FOURTH-ORDER FINITE DIFFERENCE METHODS

  • Bak, Soyoon;Kim, Philsu;Park, Sangbeom
    • Journal of the Korean Mathematical Society
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    • v.59 no.5
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    • pp.891-909
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    • 2022
  • The main objective of this paper is to develop a concrete inverse formula of the system induced by the fourth-order finite difference method for two-point boundary value problems with Robin boundary conditions. This inverse formula facilitates to make a fast algorithm for solving the problems. Our numerical results show the efficiency and accuracy of the proposed method, which is implemented by the Thomas algorithm.

Updating Algorithms of Finite Element Model Using Singular Value Decomposition and Eigenanalysis (특이값 분해와 고유치해석을 이용한 유한요소모델의 개선)

  • 김홍준;박영필
    • Journal of KSNVE
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    • v.9 no.1
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    • pp.163-173
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    • 1999
  • Precise and reasonable modelling is necessary and indispensable to the analysis of dynamic characteristics of mechanical structures. Also. the effective prediction of the change of modal properties due to the variation of design parameters is required especially for the application of finite element method to the structural dynamics problems. To meet those necessity and requirement, three model updating algorithms are proposed for finite element methods. Those algorithms are based on sensitivity analysis of the modal data obtained from experimental modal analysis(EMA) and analytical modal analysis(AMA). The adapted sensitivity analysis methods of the algorithms are 1)eigensensitivity(EGNS) method. 2)frequency response function sensitivity(FRFS) method. 3)sensitivity based element-by-element method (SBEEM), Singular value decomposition(SVD) is used for performing eigenanalysis and parameter estimation in the updating process. Those algorithms are applied to finite element of a plate and the updating capability of each algorithm is compared in terms of accuracy. reliability and stability of the updating process. It is shown that the model updating method using frequency response function is superior to the other methods in view of various updating capabilities.

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A Study on Seepage line of Dam body by Finite Element method and Experiment. (이론 및 실험에 의한 제체의 침윤선에 관한 연구)

  • 신문섭;안상진
    • Water for future
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    • v.14 no.2
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    • pp.53-62
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    • 1981
  • In the Hydraulic Structure, Such as dam body or levee of river that is constructed with soil, We analyzed a top line of free ground water table. This study is based on the logical reason that the pressure on the free surface is atmospheric and the seepage line is a stream line. In order to research for the unknown seepage line. We analyzed seepage water of steady flow through parous media by Finite Element method based on Galerkin Principle, and compared the comluted value with experimental value. The results show that the computed value was nearly equal to the experimental value. Finally, it noticed that finite Element method was more practical than Experimental Method for Seepage line analysis.

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Detection of a Crack in Beams by Eigen Value Analysis (고유치 해석을 이용한 보의 크랙 탐색)

  • Lee, Hee-Su;Lee, Ki-Hoon;Cho, Jae-Hoon
    • Proceeding of EDISON Challenge
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    • 2016.03a
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    • pp.195-202
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    • 2016
  • In this paper, crack detection method using eigen value analysis is presented. Three methods are used: theoretical analysis, finite element method with the cracked beam elements and finite element method with three dimensional continuum elements. Finite element formulation of the cracked beam element is introduced. Additional term about stress intensity factor based on fracture mechanics theory is added to flexibility matrix of original beam to model the crack. As using calculated stiffness matrix of cracked beam element and mass matrix, natural frequencies are calculated by eigen value analysis. In the case of using continuum elements, the natural frequencies could be calculated by using EDISON CASAD solver. Several cases of crack are simulated to obtain natural frequencies corresponding the crack. The surface of natural frequency is plotted as changing with crack location and depth. Inverse analysis method is used to find crack location and depth from the natural frequencies of experimental data, which are referred by another papers. Predicted results are similar with the true crack location and depth.

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FOURTH ORDER ELLIPTIC BOUNDARY VALUE PROBLEM WITH SQUARE GROWTH NONLINEARITY

  • Jung, Tacksun;Choi, Q-Heung
    • Korean Journal of Mathematics
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    • v.18 no.3
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    • pp.323-334
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    • 2010
  • We give a theorem for the existence of at least three solutions for the fourth order elliptic boundary value problem with the square growth variable coefficient nonlinear term. We use the variational reduction method and the critical point theory for the associated functional on the finite dimensional subspace to prove our main result. We investigate the shape of the graph of the associated functional on the finite dimensional subspace, (P.S.) condition and the behavior of the associated functional in the neighborhood of the origin on the finite dimensional reduction subspace.