Study on a Hexagonal Acoustic Metamaterial Cell of Multiple Parallel-Connection Resonators with Tunable Perforating Rate

Abstract

The limited occupied space and various noise spectrum requires an adjustable sound absorber with a smart structure and tunable sound absorption performance. The hexagonal acoustic metamaterial cell of the multiple parallel-connection resonators with tunable perforating rate was proposed in this research, which consisted of six triangular cavities and six trapezium cavities, and the perforation rate of each cavity was adjustable by moving the sliding block along the slideway. The optimal geometric parameters were obtained by the joint optimization of the acoustic finite element simulation and cuckoo search algorithm, and the average sound absorption coefficients in the target frequency ranges of 650–1150 Hz, 700–1200 Hz and 700–1000 Hz were up to 0.8565, 0.8615 and 0.8807, respectively. The experimental sample was fabricated by the fused filament fabrication method, and its sound absorption coefficients were further detected by impedance tube detector. The consistency between simulation data and experimental data proved the accuracy of the acoustic finite element simulation model and the effectiveness of the joint optimization method. The tunable sound absorption performance, outstanding low-frequency noise reduction property, extensible outline structure and efficient space utilization were favorable to promote its practical applications in noise reduction.

Sustainable Perforated Acoustic Wooden Panels Designed Using Third-Degree-of-Freedom Bezier Curves with Broadband Sound Absorption Coefficients

“…The impedance tube simulation model was prepared using previously described methods [28,29]. Similar research was also presented in [17,18]. Concerning the total sample size diameter (500 mm), the upper frequency available to simulate was 550 Hz.…”

“…For α size , a rectangular sample was used with a size of 3 × 3.5 m as it reflected the required conditions for the later ISO 354 [37] measurements. The computational environment in [18] offered a similar solution but with an overall sample diameter of up to 100 mm, which allowed the upper simulation frequency to be 1400 Hz. In the current case, the panel sample could not be reduced as it had to reflect the possible final design of the panels, and the modeling of just a part of the panel did not provide any useful information for this research.…”

“…In this paper, we assumed the panel surface to be flat and followed a similar approach for a different material: a wooden 3D perforated panel with a porous backing. Recently, the research on sound-absorbing materials has mainly been focused on metamaterial panel development [ 17 , 18 ], and the methods, such as a combination of FEM modeling and impedance tube testing, can be adapted to other types of acoustic panels.…”

Machine Intelligence in Metamaterials Design

“…1754 Cuckoos can lay eggs (representing candidate designs) in 1755 nests (representing solutions) to explore and improve the 1756 design space[93]. Examples of CS in metamaterials de-1757 sign include the work of Yang et al[209] whose focus was 1758 on acoustic metamaterials with multiple parallel hexagonal 1759 Helmholtz resonators, more recently researched by[210], 1760 Yang et al[211] whose work focused on the structural pa-1761 rameterization of metamaterials for sound absorption, and 1762 the development of thin multi-layer metamaterial sound 1763 absorbers through CS based parameter optimization[212].1764 Our analyses reveal that the most popular techniques, by 1767 the number of publications, are evolutionary algorithms 1768 and artificial neural networks. A summary of methods 1769 is provided in four separate tables in the Appendix, fo-1770 cusing on ANN (Appendix Table1), ML excluding ANN 1771 (Appendix Table2), nature inspired AI (Appendix Table17723), and combined methods (Appendix Table4).…”