Ultra-ventilated sound absorption metamaterial lamina

Abstract We propose a lamina-shaped metamaterial absorber based on the coherently coupled weak resonances of high-order Helmholtz resonators in this work. Such an ultra-thin lamina metamaterial can achieve broadband tunable absorption (maximal absorption >0.9), which exhibits near-perfect ventilation performance (ventilated area ratio >0.8, ratio of wind velocity >0.95). Benefiting from coherently coupled weak resonances between units with different structure parameters, the lamina metamaterial presents a broadband absorption (506–659 Hz with 2 × 3 units and 480–679 Hz with 2 × 4 units). The ultra-thin and simple structure shape of this sound absorption metamaterial lamina leads to not only an efficient ventilation performance but also high potential value in various scenarios of ventilated sound absorption, especially in ventilation tubes with high noise.