贴附型局域共振声子晶体双层板的带隙特性

针对板面之间周期性贴附柱状散射体的局域共振声子晶体双层板结构,采用有限元法计算了该结构能带结构、特征模态所对应的位移场以及相应有限周期双层板结构的传输曲线,对其展现出的带隙特性进行了研究。数值结果和分析表明,当激励点和响应点位于上下异侧板时,一条起始频率低并且带隙宽的完全带隙可以被打开。该带隙的打开可以认为是共振单元的振动模态和上下板的板振动模态相互耦合作用的结果。同时,由双板间空气声腔所带来的声振耦合效应对带隙的影响可以忽略不计。此外,双层板结构展现出许多相应单板结构共同的带隙特性,但其拥有单板所无法比拟的宽带隙特性。通过改变结构相关参数,可以实现对带隙的有效调节。

Bandgap Properties in Stubbed-on Locally Resonant Phononic Crystal Double Panel Structures

The stubbed-on locally resonant (LR) phononic crystal double panel structure made of a two-dimensional periodic array of a cylindrical LR pillar connected between the upper and lower plates is constructed, and the bandgap properties of the structure are investigated in detail. The band structures, displacement fields of eigenmodes and transmission power spectrums of the corresponding finite structure are calculated by a finite element method. Numerical results and the further analysis demonstrate that a band gap with a low starting frequency and a wide band width is opened by the coupling between dominant vibrations of the pillars and plate modes, if the vibration source and receiver are considered on different sides of the structure. In addition, the influence of coupling between sound and vibration in the cavity on the band gap can be ignored. Many common characteristics are displayed between the double panel and the corresponding single plate, but the double panel structure has the excellent property of wide band gap. By changing the relevant parameters of the structure, the band gap can be adjusted effectively.