Unveiling the structure-property relationships of multilayered Helmholtz resonance-based acoustic metamaterials

The principle of Helmholtz resonance has been widely employed in the design of sound-absorbing metamaterials. However, the relationship between various acoustic parameters and sound absorption performance remains insufficiently understood. This work investigates the effect of various structural parameters of multi-layered Helmholtz resonators (MLHRs) on sound absorption properties from a statistical point of view. The Taguchi method was used in the study with the pore diameter, pore thickness, and cavity depth of a layer of Helmholtz resonator as control variables and the number of layers of resonators as the noise variable. Results revealed a clear hierarchy of importance for maximizing sound absorption: increasing the number of layers, reducing pore diameter, enhancing pore thickness, and expanding cavity depth. Additionally, it is also found that the influence of the number of layers on said relationships was greatest with smaller pore diameters larger pore thicknesses, and cavity depths. All three control variables showed significant effects on the sound absorption properties of MLHRs when the number of layers was more than two, while the cavity width showed limited influence on sound absorption coefficients for a two-layer MLHR. This work provides a foundational understanding of the structural-property relationships in MLHRs, paving the way for optimized designs to achieve optimal sound absorption performance.