Sound Absorption of Microperforated Panels in Complex Vibroacoustic Environments

The application of Miro-Perforate Panels (MPP) goes beyond their initial realm in environmental and architectural acoustics, in which a simple acoustic field is usually considered, either diffuse or plane wave in most cases, where a MPP is usually treated as a sound absorption material with its acoustic properties characterized by the surface impedance or sound absorption coefficient. When used in more realistic and definitely more complex systems, evidence shows that the MPP is coupled to the surrounding acoustic environment so that its in-situ sound absorption is strongly affected. While the observation may inspire designs of new MPP absorbers by taking advantages of the vibroacoustic coupling principles, the increasing system complexities impose great challenges in terms of system modelling for the analysis and optimization of the MPP performance in a complex vibro-acoustic environment. Versatility, efficiency and flexibilities are the most important attributes required for such simulation tools. This paper examines these issues by summarizing the work carried out by our research group in the past few years. The in-situ sound absorption behaviour of MPPs in various vibroacoustic environments, the modelling of their coupling with the surrounding acoustic medium, the underlying sound absorption physics as well as the influence of grazing flows are discussed.