Design of a honeycomb-microperforated panel with an adjustable sound absorption frequency

An adjustable sound absorption frequency honeycomb-microperforated panel (ASAFHM) structure is designed in this study. The ASAFHM structure is a unit of a honeycomb-microperforated panel (MPP) structure. A mechanical rotating mechanism was used to change the sound absorption property of MPP added in the middle of the ASAFHM core. An equivalent hybrid honeycomb-MPP model, which can be calculated using acoustoelectric analogy and transfer matrix methods, is described to predict the sound absorption of the ASAFHM structure. Experimental results demonstrate that the peak frequency can shift by approximately 14.2%. Furthermore, the maximum 0.8 absorption bandwidth can be broadened to 188% by adjustable absorption baffles under different angles. The relationship between perforation ratio and resonant frequency fitted linearly in this study can be used to design sound absorbers under complex noise environments. This study provides an effective method to adjust the sound performance of sound absorbers. The proposed honeycomb-MPP structure herein is applicable to sound absorption.