二维三组元声子晶体Schoch效应及其调控

The Schoch effect mechanism analysis and its regulation of two dimensional three components phononic crystal

本文通过改变声子晶体表面的结构,调节表面一层的结构,观测到了二维声子晶体的Schoch效应,并且Schoch位移达到晶格常数的7.1倍.根据有限元方法计算超胞带结构及声压场图,分析了二维声子晶体Schoch效应产生的物理机理.由于表面结构影响,带结构通带中出现了一条类波导模,这种类波导模的存在使得入射波部分能量传导进表面层中,最终导致反射波束发生形变和偏移.通过改变声子晶体表面层包层半径,研究了声子晶体Schoch位移的变化规律,进一步增加表面层层数,实现了声子晶体Schoch效应的调控.本文的研究成果可为基于Schoch效应的声学传感器、声开关等声学器件的设计提供一定的理论参考与指导作用.

In this paper, through changing the phononic crystal surface and adjusting the structure of surface layer, we observed the Schoch effect of two dimensional phononic crystal, and the Schoch shift reached 7.1 times of the lattice constant. To further understand the physical mechanism of this kind of phenomenon, the finite element method is used to calculate the band structure of the model. Because of the influences of the surface of structure, there exists a kind of waveguide mode in the passband. Through careful analysis of the band structure and the sound pressure field profile, it is found the kind of waveguide mode makes the incident wave energy go into the waveguide layer which resulting in reflection beam deformation and offset. In addition, through the finite element simulation, the change regulation of the Schoch shift in the phononic crystal is studied by changing the radius of the surface layer and further increase the layer number of the surface layer of the phononic crystal to achieve the control of the Schoch effect of the phononic crystal. The conclusion of this paper can provide some theoretical reference and give some guidance for the design of acoustic sensors based on Schoch effect.