On a Volume Integral Equation Used in Solving 3-D Electromagnetic Interior Scattering Problems

1997 ◽  
Author(s):  
Sherwood Samn
Keyword(s):  
Integral Equation ◽  
Volume Integral ◽  
Scattering Problems ◽  
Volume Integral Equation

Parallel Volume Integral Equation Method for Two-Dimensional Elastodynamic Analysis

2019 ◽  
Vol 16 (06) ◽  
pp. 1840025
Author(s):  
Jungki Lee ◽  
Hogwan Jeong
Keyword(s):  
Integral Equation ◽  
Wave Scattering ◽  
Integral Equation Method ◽  
Equation Method ◽  
Two Dimensional ◽  
Volume Integral ◽  
Scattering Problems ◽  
Volume Integral Equation ◽  
Parallel Volume ◽  
Volume Integral Equation Method

The parallel volume integral equation method (PVIEM) is applied for the analysis of two-dimensional elastic wave scattering problems in an unbounded isotropic solid containing various types of multiple multilayered anisotropic inclusions. It should be noted that the volume integral equation method (VIEM) does not require the use of the Green’s function for the anisotropic inclusion — only the Green’s function for the unbounded isotropic matrix is needed. A detailed analysis of the SH wave scattering problem is presented for various types of multiple multilayered orthotropic inclusions. Numerical results are presented for the elastic fields at the interfaces for square and hexagonal packing arrays of various types of multilayered orthotropic inclusions in a broad frequency range of practical interest. Standard parallel programming was used to speed up computation in the VIEM. The PVIEM enables us to investigate the effects of single/multiple scattering, fiber packing type, fiber volume fraction, single/multiple layer(s), multilayer’s shapes and geometry, isotropy/anisotropy, and softness/hardness of various types of multiple multilayered anisotropic inclusions on displacements and stresses at the interfaces of the inclusions and far-field scattering patterns. Also, powerful capabilities of the PVIEM for the analysis of general two-dimensional multiple scattering problems are investigated.

scholarly journals Versatile Solver of Nonconformal Volume Integral Equation Based on SWG Basis Function

2018 ◽  
Vol 2018 ◽  
pp. 1-7
Author(s):  
Chunbei Luo ◽  
Mingjie Pang ◽  
Hai Lin
Keyword(s):  
Integral Equation ◽  
Basis Function ◽  
High Efficiency ◽  
Low Frequency ◽  
Piecewise Constant Function ◽  
Volume Integral ◽  
Scattering Problems ◽  
Volume Integral Equation ◽  
Inhomogeneous Dielectric ◽  
Brute Force Method

In this paper, a versatile solver of a nonconformal volume integral equation based on the Schaubert-Wilton-Glisson (SWG) basis function is presented. Instead of using a piecewise constant function, the robust conventional SWG basis function is chosen and used directly for discontinuous boundaries. A new map method technique is proposed for constructing SWG pairs, which reduces the complexity from ON2 to ONlogN compared with a brute-force method. The integral equation is solved by the method of moments (MoM) and further accelerated by the multilevel fast multipole algorithm (MLFMA). What’s more, the hybrid scheme of MLFMA and adaptive cross approximation (ACA) is developed to resolve the low-frequency (LF) breakdown when dealing with over-dense mesh objects. Numerical results show that when in analysis of radiation or scattering problems from inhomogeneous dielectric objects or in LF conditions, the proposed solver shows high efficiency without loss of accuracy, which demonstrates the versatile performance of the proposed method.

Volume Integral Equation Method (VIEM)

2021 ◽  
pp. 79-138
Author(s):  
Jungki Lee
Keyword(s):  
Integral Equation ◽  
Integral Equation Method ◽  
Equation Method ◽  
Volume Integral ◽  
The Finite Element Method ◽  
Scattering Problems ◽  
Heterogeneous Solids ◽  
Volume Integral Equation ◽  
Elastic Wave Scattering ◽  
Volume Integral Equation Method

A number of analytical techniques are available for the stress analysis of inclusion problems when the geometries of inclusions are simple (e.g., cylindrical, spherical or ellipsoidal) and when they are well separated [9, 41, 52]. However, these approaches cannot be applied to more general problems where the inclusions are anisotropic and arbitrary in shape, particularly when their concentration is high. Thus, stress analysis of heterogeneous solids or analysis of elastic wave scattering problems in heterogeneous solids often requires the use of numerical techniques based on either the finite element method (FEM) or the boundary integral equation method (BIEM). However, these methods become problematic when dealing with elastostatic problems or elastic wave scattering problems in unbounded media containing anisotropic and/or heterogeneous inclusions of arbitrary shapes. It has been demonstrated that the volume integral equation method (VIEM) can overcome such difficulties in solving a large class of inclusion problems [6,10,20,21,28–30]. One advantage of the VIEM over the BIEM is that it does not require the use of Green’s functions for anisotropic inclusions. Since the elastodynamic Green’s functions for anisotropic media are extremely difficult to calculate, the VIEM offers a clear advantage over the BIEM. In addition, the VIEM is not sensitive to the geometry or concentration of the inclusions. Moreover, in contrast to the finite element method, where the full domain needs to be discretized, the VIEM requires discretization of the inclusions only.

scholarly journals Fitting Green’s Function FFT Acceleration Applied to Anisotropic Dielectric Scattering Problems

2015 ◽  
Vol 2015 ◽  
pp. 1-8
Author(s):  
Shu-Wen Chen ◽  
Feng Lu ◽  
Yao Ma
Keyword(s):  
Integral Equation ◽  
Fourier Transform ◽  
Fast Fourier Transform ◽  
Green’S Function ◽  
Green's Function ◽  
Electromagnetic Scattering ◽  
Volume Integral ◽  
Scattering Problems ◽  
Volume Integral Equation ◽  
Anisotropic Dielectric

A volume integral equation based fast algorithm using the Fast Fourier Transform of fitting Green’s function (FG-FFT) is proposed in this paper for analysis of electromagnetic scattering from 3D anisotropic dielectric objects. For the anisotropic VIE model, geometric discretization is still implemented by tetrahedron cells and the Schaubert-Wilton-Glisson (SWG) basis functions are also used to represent the electric flux density vectors. Compared with other Fast Fourier Transform based fast methods, using fitting Green’s function technique has higher accuracy and can be applied to a relatively coarse grid, so the Fast Fourier Transform of fitting Green’s function is selected to accelerate anisotropic dielectric model of volume integral equation for solving electromagnetic scattering problems. Besides, the near-field matrix elements in this method are used to construct preconditioner, which has been proved to be effective. At last, several representative numerical experiments proved the validity and efficiency of the proposed method.

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