二维声子晶体带隙的栅板调节作用研究

Research of the Acoustic Grating Regulating to the Band Gap of Two Dimensional Phononic Crystals

以二维铁/水正方形排列声子晶体平板为主板模型,用时域有限差分法(FDTD)分析栅板对主板声波通透性的影响,结果发现,栅板的材料、填充率、位置、厚度、密排结构等都会影响主板的声波通透性。其中,极软材料的栅,主要阻碍低频声波的传播;大填充率栅板的影响较小填充率栅板的大;多层栅板的影响较单层栅板的大;密排结构的栅板会极大地影响主板的声通透性,甚至引入高频带隙。栅板对主板的调节作用可望在声滤波、声聚焦、超声成像等方面有重要应用。

By the method of finite difference time domain （FDTI））, acoustic grating regulating to lhe band gap of two dimensional iron/water phononic crystals motherboard, with a square array, was investigated. It was found that the motherboard sound permeability is affected by acoustic grating of the material, cylinder filling rate, location, thickness, and the close-packed of the cylinders. Of these factors, very soft material cylinders in acoustic grating mainly decrease the permeability of lower frequency sounds, higher filling rate grating has a greater impact on sound propagating than the lower fill rate, multi-layer grating affects sound permeability more than the single layer. And es pecially, the sound propagating changes significantly after the close-packed cylinders are introduced in the grating, and resuh in some high frequency band gaps appearance. The acoustic grating regulating to the sound permeability of motherboard will play a key role in sound filter, sound focusing and ultrasonic imaging etc.