Air Vehicles Division, Defence Science and Technology Organisation, Melbourne, Victoria 3207, Bundoora, Vicotria 3083, Australia.
J Acoust Soc Am. 2010 Feb;127(2):754-63. doi: 10.1121/1.3277217.
The scattering of plate waves by localized damage or defects that can be modeled as flexural inhomogeneities is examined within the framework of Mindlin plate theory. These inhomogeneities are characterized by variations in one or more of the four plate-theory parameters: the bending stiffness, shear stiffness, rotary inertia, and transverse inertia. It is shown that the Born approximation for the scattered field leads to a plate-theory analog of the Fourier diffraction theorem, which relates the far-field scattering amplitude to the spatial Fourier transform of the inhomogeneity variations. The application of this result is illustrated by using synthetic data derived for an idealized model of a delamination as a flexural inhomogeneity, ignoring mode coupling effects. A computationally efficient implementation of the filtered back-propagation algorithm, based on the eigensystem of the scattering operator, is employed for image reconstruction. The implications for in-situ imaging of structural damage in plate-like structures are briefly discussed, and some directions for further work are indicated.
局部损伤或缺陷（可以模拟为弯曲不连续性）对板波的散射在 Mindlin 板理论框架内进行了研究。这些不连续性的特征在于四个板理论参数中的一个或多个发生变化：弯曲刚度、剪切刚度、转动惯量和横向惯性。结果表明，散射场的 Born 近似导致了板理论类比的傅里叶衍射定理，该定理将远场散射幅度与不均匀性变化的空间傅里叶变换相关联。通过使用作为弯曲不连续性的分层模型的理想化模型导出的合成数据来举例说明该结果的应用，忽略了模式耦合效应。基于散射算子的特征系统，采用基于滤波反投影算法的计算效率实现图像重建。简要讨论了板状结构中结构损伤的原位成像的意义，并指出了进一步工作的方向。
