含有周期球腔的黏弹性覆盖层消声性能分析

Analysis of the anechoic properties of viscoelastic coatings with periodically distributed cavities

利用散射矩阵法分析了单个球状空腔在黏弹性橡胶中的Mie散射特性以及振动模式.以此为基础,利用多重散射法分析了不同背衬条件下,含有单层周期球状空腔的橡胶覆盖层(厚度为8mm)的消声性能.结果表明,单个球腔的径向共振对覆盖层的低频消声性能有重要贡献,覆盖薄层在共振区具有良好的消声性能.最后,设计了双层消声覆盖层(厚度为20mm),有效拓展了消声带宽.

Using an exact Mie scattering solution, the scattering and vibration mode of a single air sphere in unbounded rubber are analyzed with reference to the elements of the scattering matrix. Then, using the multiple-scattering method, the anechoic properties of the viscoelastic rubber coating （with a thickness of 8 mm） containing a plane of periodically distributed air spheres are investigated under different backing conditions. The results show that the excellent anechoic performance of the coating originates from the dilatational resonance of each air sphere. The anechoic coating can attenuate most incident energy and minimize reflection in the resonance frequency region. Finally, a bi-layer coating （with a thickness of 20 mm） is designed for broad-band anechoic material.