Sound absorption of micro-perforated panels and porous layers

摘要

A sound absorption study has been performed using a micro-perforated panel and arnporous layer to investigate, predict, and optimize the acoustic performance of the layeredrnsystem. The micro-perforated panel flow resistance is modeled by Maa’s equation thatrncombines a rigid panel, where no panel motion is considered, or a membrane to account forrnmass inertia in the prediction of sound absorption performance. The rigid model is usefulrnin understanding the relationship between sound absorption performance and microperforatedrnpanel geometry. Parametric studies demonstrate changes in maximumrnabsorption frequency and amplitude resulting from changes in key micro-perforated panelrngeometry, e.g., hole diameter, hole thickness, and surface porosity. Interestingly, it is foundrnthat the ratio of hole diameter to thickness and surface porosity can be effective inrncontrolling the lower frequency range without greatly increasing the air depth of thernlayered system. The micro-perforated panel model is also formulated with the porousrnmodel based on Biot theory and the combined system can potentially be used to achieve arnbroader frequency sound attenuation than the micro-perforated panel alone. The studyrnshows the total sound absorption performance of the micro-perforated panel with porousrnlayers can be primarily defined by the higher flow resistance layer of the combined system.