Investigation on Terminal Correction in Theoretical Model of the Microperforated Panel Absorber

Abstract

Microperforated panel (MPP) absorber is promising sound absorbing structure for the noise reduction. It is extremely especially to construct accurate theoretical sound absorbing model of the MPP structure for design and development of an excellent sound absorber. Thus, modification and validation of the terminal correction in theoretical sound absorption model of the MPP absorber is investigated in this research, which aimed to improve its accuracy and reasonability. Firstly, based on the Maa’s theory, classic sound absorption model of the MPP absorber was presented and treated as basic reference of the whole research. Secondly, through a set of verification experiments, necessity and importance of the research on reasonability of terminal correction was revealed. For the superposition of several monolayer MPP absorbers, when its sound absorption coefficient was derived as the multilayer MPP absorber through the transfer matrix method, the terminal corrections for the former n-1 monolayer MPPs should be removed, because length of these MPPs was 0. Thus, it was essential to take length of the rear cavity into account for the terminal corrections in the theoretical sound absorption model of the MPP absorber.