外加磁场时磁弹性声子晶体板中波拓扑传输效应

声拓扑边界态具有背散射抑制的能力。由于流体中声波的无自旋性质, 在声学系统中对拓扑态至关重要的 “自旋” 自由度是通常利用循环背景流或预置耦合谐振环波导实现,这极大地增加了工程复杂度。本项目研究板波在外加磁场时声子晶体板中的非互易性传输和拓扑传输：首先研究板波在外加静态磁场时磁弹性声子晶体板的非互易性和拓扑态传输；接着研究板波在外加静态磁场时磁弹性声子晶体板的主动可调拓扑态传输；并详细分析板波在外加动态磁场时磁弹声子晶体板中的非互易性传输和拓扑传输；最后实验验证实验验证外加动态磁场时二维磁弹性声子晶体板中兰姆波可调拓扑传输。为外加磁场时超材料拓扑态的超声表征与检测提供必要的理论依据；并为板波的拓扑态传输的工程应用提供理论和实验基础。

Acoustic topological edge states have the ability to suppress back-scattering. Because of the spinless nature of acoustic waves in fluid regime, the “spinlike” degree of freedom crucial to topological states in acoustic systems is commonly realized with circulating background flow or preset coupled resonator ring waveguides, which drastically increases the engineering complexity. In this project, the topological transmission properties of plate-mode waves in phononic crystal slabs are studied by an applied external magnetostatic field. Firstly, the nonreciprocal wave propagation and topological state transmission of magneto - elastic phononic crystal is studied in that case of a applied external statics magnetic field. Then, the tunable topological state transmission of the magneto - elastic phononic crystal is studied when the external statics magnetic field is applied. Meanwhile, we particularly analyze the nonreciprocal wave propagation and topological state transmission of magneto - elastic phononic crystal in that case of an applied external dynamic magnetic field. Finally, the experimental results verify the topological state transmission of the plate wave in magneto - elastic phononic crystal slabs by an applied external dynamic magnetic fields. It provides the necessary theoretical evidence for the ultrasonic characterization and detection of the topological state in the metamaterials when the external magnetic field is applied, and provides the theoretical and experimental basis for the engineering application of the topological state transmission of plate-mode waves.