A rigid microperforated panel combined with a finite-depth air space can absorb sound effectively. Various studies of these systems have been performed and it has been found that hole configuration and backing depth are the primary factors that determine their absorption. However, the effects of panel flexibility and the finite size of the supported membrane segments have not been considered as extensively. In this present work, a two-dimensional model for arbitrary incidence angles was used to predict the sound absorption of an infinite array of finite-size, flexible microperforated panels. The absorption of various microperforated panels was measured in standing wave tubes and compared to predictions to verify the model at normal incidence. The effects of two different types of backing spaces, i.e., segmented and unsegmented, were compared. It was found that the segmented backing space is approximately locally reacting: as a result, the absorption at low frequencies is larger than that for the unsegmented backing space case. It was also found that the absorption from an array of finite-size microperforated panels can be successfully predicted with a knowledge of the panel’s physical material properties (e.g., flexural stiffness, loss factor, and mass per unit area) and hole configuration (e.g., hole size, film thickness, and number of holes per unit area).
Microperforated, Sound absorption, Periodic array, Arbitrary incidence angle, Extended reaction
Acoustics and Noise Control
Date of this Version