Development of Broadband Ultra Micro-Perforated Panels Based on MEMS Technology

Abstract

Fabrication process of ultra micro-perforated panels (ultra-MPPs) with perforations of diameter below 100 um based on MEMS technology is expatiated in this paper. As a promising alternative to the conventional porous absorbing materials, MPP absorber is now being widely used in noise control engineering. Theory reveals that the maximum sound absorption bandwidth of a single MPP absorber could be achieved by reducing the perforation diameter to a certain limit and the desirable perforation diameters are less than 100um under many circumstances. However, due to the limitation of traditional manufacturing tools and techniques, MPPs with ultra-micro perforations of diameter less than 100um, namely for ultra micro-perforated panel (ultra-MPPs), have seldom been investigated yet. In this study, micro electro mechanical systems (MEMS) technology was applied to a trial production of ultra-MPPs and the measurement of their normal absorption coefficients were carried out in the impedance tube. Results show that ultra-MPPs could attain high absorption over a broad frequency range, indicating that as a micro machining process, MEMS technology is suitable for fabricating ultra-MPPs in order to ensure the absorption performance.

Causal-based optimization of micro-perforated treatments

“…Enlarging the absorption bandwidth can be achieved from a parallel distribution of MPP resonance absorbers [9] with a suitable placement of the individual cell first-and multiple-order resonances [8,10] to avoid dips between the absorption peaks. Alternatively, this can be realized from the use of ultra-MPPs [11] or purely resistive microcapillary plates [12] with micrometric hole diameters and calibrated transfer impedance. Extending the absorption performance towards low-frequencies while satisfying space-saving constraints has been addressed used coiled intricate cavities [8,10] or long extended necks [5] behind the MPPs.…”

An Empirical Model for Optimizing the Sound Absorption of Single Layer MPP Based on Response Surface Methodology

“…Aimed for a wide absorption bandwidth; many studies have been presented on a single layer MPP using various techniques. This includes the presents of the MPP model with incompletely partitioned cavities (Huang et al, 2017) broadband MPP model with ultra-MPP (Qian et al, 2014a); thin MPP models (Prasetiyo et al, 2021), inhomogeneous MPP systems with multiple cavity depths (Prasetiyo et al, 2016;Mosa et al, 2019;Kusaka et al, 2021).…”