Micro-perforated acoustic metastructure for low-frequency sound absorption and ventilation

We present an acoustic metastructure that features a micro-perforated resonator to combine broadband sound absorption with efficient ventilation. Adjusting the perforation parameters enables micro-perforated resonators to have a range of absorption states. Based on this diversity, the optimal resonators are selected for continuous and effective sound absorption. Analytical, numerical, and experimental results demonstrate that the absorption coefficient of the proposed metastructure exceeds 0.8 across the frequency range from 464 to 786 Hz, with a thickness of only 1/20 of the operating wavelength. Experimental results indicate a ventilation efficiency of 0.74 for airflow and 0.82 for heat flux compared to an open condition. These results have the potential to expand the application of acoustic metamaterials, particularly in space-constrained environments that require effective noise absorption and air circulation.