In this work, a double-layer honeycomb microperforated structure with adjustable back-cavity’s height is designed based on cylinder honeycomb structure and microperforated panel (MPP). The sound absorption performance can be changed by adjusting the height of back-cavity. Thus, a better absorption performance is achieved by changing the position of the inner MPP. Acoustic impedance of the structure was calculated based on transfer matrix method. The sound absorption coefficient of the structure was obtained by finite element method (FEM). Meanwhile, the 3D printing technology was used to produce the experimental samples. The experimental results demonstrate that the sound absorption coefficient of the structure is greater than 0.8 in the range of 750–1250 Hz, greater than 0.9 in the range of 2297–3592 Hz, and above 0.5 in the range of 500–4000 Hz. In addition, the feasibility of achieving adjustable sound absorption by means of changing the height of the back-cavity is verified by theoretical, simulation, and experimental results. The structure proposed in this work can realize the function of wide-band and better sound absorption performance by changing the position of the inner MPP, which can be applied to effectively reduce different frequencies noise.

中文翻译：

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吸声性能可调的蜂窝微孔结构设计

在这项工作中，基于圆柱蜂窝结构和微穿孔板（MPP）设计了一种具有可调背腔高度的双层蜂窝微穿孔结构。可通过调整背腔高度来改变吸声性能。因此，通过改变内部 MPP 的位置可以获得更好的吸收性能。基于传递矩阵法计算结构的声阻抗。结构的吸声系数通过有限元法（FEM）获得。同时，3D打印技术被用于生产实验样品。实验结果表明，该结构的吸声系数在750-1250Hz范围内大于0.8，在2297-3592Hz范围内大于0.9，在500-4000Hz范围内大于0.5。此外，通过理论、仿真和实验结果验证了通过改变背腔高度来实现可调吸声的可行性。本工作提出的结构可以通过改变内部MPP的位置来实现宽带功能和更好的吸声性能，可用于有效降低不同频率的噪声。