A tunable slit-plate absorber with multiparameter cooperative control

Abstract

Tunable acoustic metamaterials have a more flexible operating spectrum while still controlling acoustic waves via subwavelength thickness, but their operating range and acoustic absorption performance are limited by a single-parameter tuning mechanism. In this study, we first propose a slit-plate absorber with reconstructed porosity, which has a dynamic continuous tuning capability and is easier to achieve low-frequency resonance. Then, in order to improve its acoustic absorption performance, we study the tuning laws of numerous structural factors as well as their cooperative interaction. Local parameter changes to achieve impedance compensation and isotropic control to enhance frequency shift are presented to greatly improve the tunable range and sound absorption level. A tunable absorber with multi-parameter cooperative control is constructed using this method. The results reveal that continuous tuning of 210–920 Hz is possible at a total thickness of 25 mm, and the sound absorption coefficient in the tuning range is more than 0.8, and the thickness of the structure at 210 Hz is 1/65 of the absorption wavelength. Our work demonstrates a new method for improving the performance of adjustable acoustic metamaterials and promotes the use of acoustic metamaterials in low frequency changing noise environments.