Rudimentary Researches On The Acoustic Characteristics Of Microperforated Panel Absorbers With Alterable Air-Cavity

The theoretical principles of Microperforated panel (MPP) were set forth firstly by Maa D-Y in 1975. He created the MPP absorbers that can be designed by calculation. Furthermore, in 1997, he pointed out the general theory in the field of MPP absorbers and revealed the relationship between maximal absorption coefficient and utmost frequency band of MPP.MPP absorber has a variety of advantages, such as heat-resistant, moisture-proof, dust-proof, corrosion-resistant, easy-clean and so forth. It is widely used in the industry, where high temperature, high humidity, high flow or high cleanliness is required. And it can also be used in those areas as halls which require high fireproof or moisture-proof, for example, natatorium, stadium and chamber. In recent years, to fulfill the need of space layout or other requirements, MPP absorber with alterable air-cavity structure is highly emphasized. However, this is often completed after a large number of tests ahead of engineering application. That not only greatly delays the design and development cycle in MPP absorber with alterable air-cavity, but also declines the efficiency.The present paper intended to theoretically analyze and calculate absorption coefficient. Particularly, the absorption coefficient of MPP absorber with alterable air-cavity was carried out by the primary study via theoretical calculation. In this study, the quantitative and qualitative analysis on the absorption was utilized with the calculation results of absorption coefficient. Following that, the method of analysis on the absorption properties of MPP absorber with alterable air-cavity, instead of experimental analysis, was tried to be found out. This method made absorber design procedure more quickly and accurately than ever.In this paper the study object was MPP absorber with alterable air-cavity. Based on Maa's theory and the electro-acoustical analogy and with the help of MATLAB to conduct computer simulation, the formula of the absorption coefficient was educed. The paper analyzed and predicted the acoustical performance according to theoretical calculation results. In the end the paper discussed the significances of the research results stated above and the application of the results in engineering application.The primary research of theoretical calculation on acoustic absorption coefficient of the MPP absorber with alterable air-cavity is significant. It provides some guideline and advice to further research in the calculation on acoustic absorption coefficient of composite absorption materials, composite absorption structures, or absorbers with all forms of complicated space absorption as well.