The volume-surface integral equation(VSIE) ,the surface integral equation(SIE) and the volume integral equation(VIE) of EM scattering problem are converted into linear equations with the method of moment,then the prec...The volume-surface integral equation(VSIE) ,the surface integral equation(SIE) and the volume integral equation(VIE) of EM scattering problem are converted into linear equations with the method of moment,then the precorrected-FFT method is used to solve the linear equations.To overcome the drawback of conventional stencil topology,two kinds of improved stencil topology,stencil topology B and stencil topology C,are presented,and the construction and actual performance of the three kinds of stencil topology are compared.Numerical results show that good agreement is observed between the P-FFT solutions combined with each of the three kinds of stencil topology and the standard solutions.Stencil B can significantly reduce the number of near-zone precorrections.Stencil C potentially holds for parallel multilevel P-FFT since grid overlapping never occurs between any stencils.展开更多
A computational model is proposed for short-fiber reinforced materials with the eigenstrain formulation of the boundary integral equations （BIE） and solved with the newly developed boundary point method （BPM）. The...A computational model is proposed for short-fiber reinforced materials with the eigenstrain formulation of the boundary integral equations （BIE） and solved with the newly developed boundary point method （BPM）. The model is closely derived from the concept of the equivalent inclusion Of Eshelby tensors. Eigenstrains are iteratively determined for each short-fiber embedded in the matrix with various properties via the Eshelby tensors, which can be readily obtained beforehand either through analytical or numerical means. As unknown variables appear only on the boundary of the solution domain, the solution scale of the inhomogeneity problem with the model is greatly reduced. This feature is considered significant because such a traditionally time-consuming problem with inhomogeneity can be solved most cost-effectively compared with existing numerical models of the FEM or the BEM. The numerical examples are presented to compute the overall elastic properties for various short-fiber reinforced composites over a representative volume element （RVE）, showing the validity and the effectiveness of the proposed computational modal and the solution procedure.展开更多
The boundary-volume integral equation numerical technique can be a powerful tool for piecewise heterogeneous media, but it is limited to small problems or low frequencies because of great computational cost. Therefore...The boundary-volume integral equation numerical technique can be a powerful tool for piecewise heterogeneous media, but it is limited to small problems or low frequencies because of great computational cost. Therefore, a restarted GMRES method is applied to solve large-scale boundary-volume scattering problems in this paper to overcome the computational barrier. The iterative method is firstly applied to responses of dimensionless frequency to a semicircular alluvial valley filled with sediments, compared with the standard Gaussian elimination method. Then the method is tested by a heterogeneous multilayered model to show its applicability. Numerical experiments indicate that the preconditioned GMRES method can significantly improve computational efficiency especially for large Earth models and high frequencies, but with a faster convergence for the left diagonal preconditioning.展开更多
文摘The volume-surface integral equation(VSIE) ,the surface integral equation(SIE) and the volume integral equation(VIE) of EM scattering problem are converted into linear equations with the method of moment,then the precorrected-FFT method is used to solve the linear equations.To overcome the drawback of conventional stencil topology,two kinds of improved stencil topology,stencil topology B and stencil topology C,are presented,and the construction and actual performance of the three kinds of stencil topology are compared.Numerical results show that good agreement is observed between the P-FFT solutions combined with each of the three kinds of stencil topology and the standard solutions.Stencil B can significantly reduce the number of near-zone precorrections.Stencil C potentially holds for parallel multilevel P-FFT since grid overlapping never occurs between any stencils.
基金Project supported by the National Natural Science Foundation of China (No.10772106)
文摘A computational model is proposed for short-fiber reinforced materials with the eigenstrain formulation of the boundary integral equations （BIE） and solved with the newly developed boundary point method （BPM）. The model is closely derived from the concept of the equivalent inclusion Of Eshelby tensors. Eigenstrains are iteratively determined for each short-fiber embedded in the matrix with various properties via the Eshelby tensors, which can be readily obtained beforehand either through analytical or numerical means. As unknown variables appear only on the boundary of the solution domain, the solution scale of the inhomogeneity problem with the model is greatly reduced. This feature is considered significant because such a traditionally time-consuming problem with inhomogeneity can be solved most cost-effectively compared with existing numerical models of the FEM or the BEM. The numerical examples are presented to compute the overall elastic properties for various short-fiber reinforced composites over a representative volume element （RVE）, showing the validity and the effectiveness of the proposed computational modal and the solution procedure.
基金supported by the National Natural Science Foundation of China(Nos. 41130418 and 40925013)the National Basic Research Program(973 Program)(No.2009CB219403)
文摘The boundary-volume integral equation numerical technique can be a powerful tool for piecewise heterogeneous media, but it is limited to small problems or low frequencies because of great computational cost. Therefore, a restarted GMRES method is applied to solve large-scale boundary-volume scattering problems in this paper to overcome the computational barrier. The iterative method is firstly applied to responses of dimensionless frequency to a semicircular alluvial valley filled with sediments, compared with the standard Gaussian elimination method. Then the method is tested by a heterogeneous multilayered model to show its applicability. Numerical experiments indicate that the preconditioned GMRES method can significantly improve computational efficiency especially for large Earth models and high frequencies, but with a faster convergence for the left diagonal preconditioning.
