Home / Journals / CMES / Vol.94, No.6, 2013
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  • Open Access

    ARTICLE

    FEM/Wideband FMBEM Coupling for Fluid-Structure Interaction Problem and 2D Acoustic Design Sensitivity Analysis

    L.L. Chen1, H.B. Chen2, C.J. Zheng3
    CMES-Computer Modeling in Engineering & Sciences, Vol.94, No.6, pp. 459-483, 2013, DOI:10.3970/cmes.2013.094.459
    Abstract A coupling algorithm based on the finite element method and the wideband fast multipole boundary element method (FEM/wideband FMBEM) is proposed for the simulation of fluid-structure interaction and structural-acoustic sensitivity analysis using the direct differentiation method. The wideband fast multipole method (FMM) formed by combining the original FMM and the diagonal form FMM is used to accelerate the matrix-vector products in the boundary element analysis. The iterative solver GMRES is applied to accelerate the solution of the linear system of equations. The FEM/Wideband FMBEM algorithm makes it possible to predict the effects of arbitrarily shaped vibrating structures on the sound… More >

  • Open Access

    ARTICLE

    Fast Boundary Knot Method for Solving Axisymmetric Helmholtz Problems with HighWave Number

    J. Lin1, W. Chen1,2, C. S. Chen3, X. R. Jiang4
    CMES-Computer Modeling in Engineering & Sciences, Vol.94, No.6, pp. 485-505, 2013, DOI:10.3970/cmes.2013.094.485
    Abstract To alleviate the difficulty of dense matrices resulting from the boundary knot method, the concept of the circulant matrix has been introduced to solve axi-symmetric Helmholtz problems. By placing the collocation points in a circular form on the surface of the boundary, the resulting matrix of the BKM has the block structure of a circulant matrix, which can be decomposed into a series of smaller matrices and solved efficiently. In particular, for the Helmholtz equation with high wave number, a large number of collocation points is required to achieve desired accuracy. In this paper, we present an efficient circulant boundary… More >

  • Open Access

    ARTICLE

    ACA-accelerated Time Domain BEM for Dynamic Analysis of HTR-PM Nuclear Island Foundation

    Haitao Wang1,2, Zhenhan Yao3
    CMES-Computer Modeling in Engineering & Sciences, Vol.94, No.6, pp. 507-527, 2013, DOI:10.3970/cmes.2013.094.507
    Abstract This paper presents the use of a three-dimensional time domain boundary element method (BEM) in conjunction with adaptive cross approximation method (ACA) for dynamic analyses of the HTR-PM nuclear island foundation. The advantage of this approach is that only foundation of the HTR-PM nuclear island and limited surfaces of the supporting half-space soil medium are modeled and analyzed in a direct time stepping scheme. In addition, the ACA can compress the BEM coefficient matrices at each time step efficiently, therefore allowing larger models to be analyzed compared with conventional BEMs. In order to discretize the boundary integral equation (BIE) we… More >

  • Open Access

    ARTICLE

    Numerical Determination on Effective Elastic Moduli of 3-D Solid with a Large Number of Microcracks using FM-DBEM

    Hongtao Wang1,2, Haitao Wang2, Lie Jin2, Zhenhan Yao3
    CMES-Computer Modeling in Engineering & Sciences, Vol.94, No.6, pp. 529-552, 2013, DOI:10.3970/cmes.2013.094.529
    Abstract Since only the boundary of the analyzed domain needs to be discretized, the boundary element method (BEM) inherently has the advantages of solving crack problems. In this paper, a micromechanics BEM scheme is applied to determine the effective elastic moduli of three-dimensional (3-D) solids containing a large number of parallel or randomly oriented microcracks. The 3-D analyses accelerated by the fast multipole method were carried out to investigate the relations between the effective elastic moduli and the microcrack density parameter. Numerical examples show that the results agree well with the available analytical solution and known micromechanics models. From the numerical… More >

  • Open Access

    ARTICLE

    Time Domain BIEM with CQM Accelerated with ACA and Truncation for the Wave Equation

    H. Yoshikawa1, R. Matsuura2, N. Nishimura1
    CMES-Computer Modeling in Engineering & Sciences, Vol.94, No.6, pp. 553-565, 2013, DOI:10.3970/cmes.2013.094.553
    Abstract The convolution integrals with respect to time in the time domain boundary integral equation method (TD-BIEM) are calculated approximately using the Lubich convolution quadrature method (CQM). The influence matrices in the discretized boundary integral equation are computed with the Laplace transform of the fundamental solution in TD-BIEM with the Lubich CQM. These matrices, however, are dense, and both the computational cost and memory requirements are high. In this paper, we apply Adaptive Cross Approximation (ACA) to the influence matrices to achieve a fast solver of TD-BIEM with the Lubich CQM. Moreover, we reduce the computational time of TD-BIEM with the… More >

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