具有深度亚波长厚度的共面可调完美吸声板

A tunable coplanar perfect sound absorbing panel with deep subwavelength thickness

针对具有深度亚波长厚度的声学超构吸声板,研究了其声学特性和物理吸声机制,以及进一步提高其低频声学特性的可能性。该吸声板单元通过将带有小孔的分隔板内置于以阿基米德螺旋形成的共面腔体中形成双层穿孔吸声体结构。研究表明,通过调整分隔板在腔体中的位置,可以在较宽的频带范围内改变吸声板的共振频率,而不改变其近似完美吸声的声学性能。对该吸声板建立了完整的用于描述其声学特性的理论模型,并通过数值模拟的方法揭示了其物理吸声机制。同时,研究并分析了吸声板结构参数对其声学特性的影响,为进一步改善其低频声学性能提供了基础。为了验证研究结论的有效性,采用3D打印技术对所设计的样品进行打印,测量结果与理论计算和数值模拟得到的结果具有很好的一致性。与未加入分隔板的吸声结构相比,该吸声板可以在更低的频率下获得近全吸声的效果。

The acoustic characteristics and physical absorption mechanism of the sound absorbing panels with deep subwavelength thickness are studied,and the possibility of further improving its low-frequency performance is also discussed.The absorber unit is a double layer perforated panel absorber that is constructed by inserting a separating plate with a small hole into the coiled coplanar air chamber which is bent in the Archimedean spiral.By adjusting the location of the separating plate in the chamber,it is found that the resonance frequency of the absorber can be easily tuned over a large bandwidth while the structural parameters are fixed,and do not change its near-total absorption properties.A complete mathematical model of the absorbing panel that describes its absorption characteristics is derived,and the physical absorption mechanism of the panel is also revealed by numerical simulation.Meanwhile,the effects of structural parameters on the absorption characteristics are also investigated,which provides a basis for further improving its low-frequency performance.To verify the validity of the research conclusion,samples have been designed and fabricated by 3D printing,and the results are all in good agreement.Compared with the previous techniques,near-total absorption can be received at a lower frequency.