应用Poisson板理论求解S0兰姆波在通孔缺陷的散射

为降低3D精确理论散射场求解的复杂性和计算成本,应用Poisson板理论描述面内波模式,给出了S0波在各向同性板中受通孔散射的近似模型。该理论利用波函数展开技术以及孔边缘的边界条件,得到了S0和SH0模式的散射远场。将Poisson板理论与3D精确理论进行比较,两者在低频情况下具有较好的一致性。考察了两个基本导波模式在不同尺寸孔的散射特性,发现它们的散射波幅值在某些散射方向随孔径呈线性变换,该结果为兰姆波无损评价提供了依据。

Poisson plate theory for solving S0 Lamb wave scattering from a through hole

To reduce the complexity and computational cost of solving scattering fields with the exact 3D model, an approximate model of S0 Lamb wave scattering from a through hole in isotropic plates is presented by using Poisson plate theory for describing in-plane wave modes. The model makes use of the wave function expansion technique and the boundary conditions at the edge of hole to obtain the far scattering fields of S0 and SH0 modes. Compared to the exact 3D model, the obtained results of Poisson model show a good agreement with those of the 3D model at low frequency. The scattering characteristics of two fundamental guided wave modes for the holes of different sizes are also explored. It is found that the scattering wave amplitudes at some scattering angles change linearly with the hole diameter, which provides a quantitative basis for Lamb wave non-destructive evaluation.