Broadband high-efficiency meta-structures design by acoustic critical absorption effect

For resonant-type meta-structures with finite dimensions and consisting of multiple units, their sound absorption performance varies with the placement of the units. In order to reveal the physical mechanism of this phenomenon and obtain the structural design rules to achieve optimal sound absorption perfor-mance, the acoustic critical absorption effect is proposed in this paper. Based on this, a 50 mm thick meta-structure is proposed, which obtains an average sound absorption performance of 70 % from 1000 Hz to 2800 Hz. Compared with a structure of the same size but without considering the acoustic critical absorption effect, the sound absorption performance of the proposed meta-structure is increased by 30 %. The high agreement between finite element simulations and experimental results verifies the reliability of the conclusions. This work provides a potential avenue for enhancing noise reduction per-formance and reducing the dimension of the structures.(c) 2022 Elsevier Ltd. All rights reserved.