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| FEM with absorbing boundary condition and expansion of discrete Chebyshev polynomials for inverse problem of elastic waves |
| Revised:November 10, 2003 |
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| DOI：10.7511/jslx20056147 |
| KeyWord:absorbing boundary condition,FEM,discrete chebyshev polynomials,defect identification |
| CHANG Jian-mei~1 FENG Huai-ping~ |
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| Abstract: |
| Research of wave motion is important both in theory and application.In this paper,it discusses an identification method of two-dimensional defect.With the combination of FEM considering absorbing boundary condition for direct problem and the expansion of discrete Chebyshev polynomials at special chosen points,the identification of two-dimensional defect in infinite area is discussed. The absorbing boundary condition is obtained through approximating the Sommerfeld radiation condition.Although the absorbing boundary condition can't simulate the effect exactly,it can satisfy the approximation in practice and has the character of solving the coupling that simplifies the calculations.Because of the use of finite element method,the direct problems that involve special geometrical shaped scattering and multi-scattering can be solved.The finite element model is used iteratively to compute the scattered field.The special points are chosen at the zeros of the Chebyshev polynomials that can achieve accuracy comparable to the general expansion with fewer terms.The numerical simulation examples show the validity of this method. |