We demonstrate experimentally the manipulation of Lamb waves guided along reconfigurable phononic circuits created by defects composed of threaded rods held with nuts in a perforated solid phononic crystal slab. Adjusting the free length of the rod, the resonant frequency of the defect can be tuned, without any change in the supporting phononic crystal slab. Both straight and bent waveguides are fabricated and measured in an aluminum sample with a lattice constant of 20 mm and a complete bandgap extending from 50 to 70 kHz. Guidance of Lamb waves is clearly observed by a Doppler vibrometer, even after 90° bends. The eigenmodes of guided waves are obtained using finite element analysis to explain the tuning of resonances through a bending cantilever model. Numerical and experimental results are generally found to be in fair agreement. They also suggest that the guiding frequency is rather independent of the details of the waveguides. They are of significance for the design of reconfigurable phononic devices.

中文翻译：

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可重构声子晶体波导中的导兰姆波

我们通过实验证明了兰姆波的操纵沿着可重构声子电路引导，该声子电路由由带螺母固定在穿孔固体声子晶体板中的螺纹杆组成的缺陷产生。调整杆的自由长度，可以调整缺陷的共振频率，而支撑声子晶体板没有任何变化。直波导和弯曲波导都是在铝样品中制造和测量的，其晶格常数为 20 毫米，完整的带隙从 50 到 70 kHz。即使在 90° 弯曲之后，多普勒振动计也能清楚地观察到兰姆波的引导。导波的本征模式是使用有限元分析获得的，以通过弯曲悬臂模型解释共振的调谐。通常发现数值和实验结果是一致的。他们还表明，引导频率与波导的细节无关。它们对于可重构声子器件的设计具有重要意义。