Control of low-frequency Lamb wave propagation in plates by boundary condition manipulation
Control of low-frequency Lamb wave propagation in plates by boundary condition manipulation
复制标题
DOI：
10.1063/5.0042576
复制
发表时间：
2021-03-07
影响因子：
3.2
通讯作者：
Shokouhi, Parisa
中科院分区：
文献类型：
--
作者：
Lissenden, Cliff J.;Hakoda, Christopher N.;Shokouhi, Parisa
局部共振亚表面可以控制兰姆波模式在平板中的传播。谐振器通常是通过频率匹配来设计的：通过反复试验调整其几何和/或材料属性，直到其谐振频率与目标兰姆波模式的频率匹配。我们证明，尽管频率匹配似乎对控制0波模是有效的，但在0波模的情况下它可能失败。本文提出了一种完全不同的方法来设计特定的亚表面，以阻止规定的兰姆波模式在板中的传播。所提出的方法是基于控制板顶面上的边界条件。表面应用不同类型的柯西边界条件来控制低频A0和0兰姆波的反射和模式转换。即使是带有修改的边界条件的小块也可以是有效的。最后，我们证明了吸收板表面柯西边界条件的局域“钳位”谐振器改变了板的色散特性，从而导致模式转换和反射。这一发现为设计特定的变形表面提供了一种合理的程序。表面安装的谐振器能够在不影响结构完整性的情况下控制板中的波传播，易于安装，并且可以改装到现有的平面结构中。数值计算结果与文献报道的实验结果吻合较好。
Locally resonant metasurfaces can control the propagation of Lamb wave modes in a plate. The resonator is typically designed through frequency matching: adjusting its geometry and/or materials properties by trial and error until its resonance frequency matches the frequency of the target Lamb wave mode. We demonstrate that although frequency matching appears effective for controlling theA 0 wave mode, it may fail in the case of theS 0 mode. This paper proposes a fundamentally different approach to design a specific metasurface to forbid the propagation of a prescribed Lamb wave mode in a plate. The proposed approach is based upon manipulating the boundary conditions on the top surface of the plate. Different types of Cauchy boundary conditions applied to the surface are shown to control the reflections and mode conversions of low-frequencyA 0 andS 0 Lamb waves. Even a small patch with the modified boundary conditions can be effective. Finally, we show that a local "clamping" resonator that assimilates Cauchy boundary conditions on the surface of the plate changes the plate dispersion characteristics resulting in mode conversion and reflection. This finding provides a rational procedure to design a specific metasurface. The surface-mounted resonators enable control of wave propagation in plates without compromising structural integrity, are easily installed, and can be retrofit to the existing planar structures. The numerical results agree well with the experimental results reported in the literature.