Investigation on acoustic performance of distributed periodic microperforated panel

In this article, an equivalent "material," called distributed periodic microperforated panel (DSPMPP), is proposed, which is formed by periodically arranging microperforated panels (MPPs). To determine a cubic DSPMPP, 4 parameters are needed, which are size of unit cell L, MPP thickness t(h), holediameterd and perforation ratio sigma. It is found that d, t(h), and sL are 3 independent parameters to determine its acoustic properties. Through a homogenization process, DSPMPP is treated as an equivalent material with equivalent density rhoc, speed of sound c(c), characteristic impedance z(c) and bulk modulus kappa(c), whose frequency dependency is similar to porous material. Acoustic performance of DSPMPP is analyzed, and compared with porous material. It is found that, choosing parameters with the provided procedure, DSPMPP can generally reproduce acoustic performance of porous material.