二维开孔式局域共振声子晶体低频带隙研究

Study on the low-frequency band gap of two-dimensional open-hole locally resonant phononic crystals

设计了一种二维开孔式局域共振声子晶体结构,结合有限元软件COMSOL计算了该结构的能带结构图及振动模态,并通过振动模态分析了该结构低频带隙产生的机理。研究结果表明,与传统的全连接结构相比,所设计的单元结构质量更加轻便,且带隙起始频率更低,可在42.34~119.81 Hz范围产生完全带隙。并在此基础上通过改变包覆层开孔半径及散射体的半径进一步分析了单元结构的带隙影响因素,其带隙的起始频率可低至29.72 Hz,可在29.72~91.93 Hz范围产生完全带隙,带宽为62.21 Hz。该结构所实现的低频带隙为声子晶体在工程实际中针对特定低频段的减振降噪应用提供了新思路。

In this article,a two-dimensional open-hole locally resonant phononic crystal is worked out;the finite-element software COMSOL is adopted to identity the energy-band structure and the vibration mode;based on the vibration mode,the analysis is conducted on the mechanism of the low-frequency band gap. The results show that the unit structure is lighter than its traditional counterpart characterized with the fully-connected structure,and the band gap has a lower starting frequency,which ensures a complete band gap in the range of 42.34~119.81 Hz. On this basis,the opening radius of the cladding layer and the radius of the scattering body are changed,in order to explore the factors which influence the band gap of the unit structure;the starting frequency of the band gap is as low as 29.72 Hz,which ensures a complete band gap in the range of 29.72~91.93 Hz,with the bandwidth of 62.21 Hz. The low-frequency band gap provides a new idea for phononic crystals in terms of vibration and noise reduction in specific low-frequency ranges in various practical fields.