Theoretical and numerical modeling of Rayleigh wave scattering by an elastic inclusion.
Theoretical and numerical modeling of Rayleigh wave scattering by an elastic inclusion.
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DOI：
10.1121/10.0017837
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发表时间：
2022-10
期刊：
影响因子：
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通讯作者：
Shan Li;Ming Huang;Yongfeng Song;B. Lan;Xiongbing Li
中科院分区：
文献类型：
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作者：
Shan Li;Ming Huang;Yongfeng Song;B. Lan;Xiongbing Li
这项工作提出了弹性夹杂物对二维瑞利波进行反向散射的理论和数值模型，其中主体材料是各向同性的，夹杂物具有任意形状和晶体学对称性。该理论模型是基于互易定理，使用远场格林函数和玻恩近似建立的，假设主体材料和夹杂材料之间的声阻抗差异很小。建立数值有限元（FE）模型是为了对散射问题进行相对准确的模拟并评估理论模型的近似值。对于具有各向同性/各向异性特性的任意形状的表面/次表面夹杂物，理论模型与有限元结果之间观察到定量一致性。当瑞利波的波长大于或相当于夹杂物的尺寸时，一致性非常好，但随着波长变小，一致性就会恶化。此外，对于各向异性对称的夹杂物，一致性随着各向异性指数的增加而降低。研究结果为利用瑞利波定量表征表层/次表层包裹体奠定了基础，同时也证明了其局限性。
This work presents theoretical and numerical models for the backscattering of two-dimensional Rayleigh waves by an elastic inclusion, with the host material being isotropic and the inclusion having an arbitrary shape and crystallographic symmetry. The theoretical model is developed based on the reciprocity theorem using the far-field Green's function and the Born approximation, assuming a small acoustic impedance difference between the host and inclusion materials. The numerical finite element (FE) model is established to deliver a relatively accurate simulation of the scattering problem and to evaluate the approximations of the theoretical model. Quantitative agreement is observed between the theoretical model and the FE results for arbitrarily shaped surface/subsurface inclusions with isotropic/anisotropic properties. The agreement is excellent when the wavelength of the Rayleigh wave is larger than, or comparable to, the size of the inclusion, but it deteriorates as the wavelength gets smaller. Also, the agreement decreases with the anisotropy index for inclusions of anisotropic symmetry. The results lay the foundation for using Rayleigh waves for quantitative characterization of surface/subsurface inclusions, while also demonstrating its limitations.