Comparative analysis of acoustic absorption performance in micro-perforated panels with multi-shaped perforations:...

This paper presents a comparison of the acoustic absorption performance of micro-perforated panel with different perforation shapes. The acoustic impedance models of different perforation shapes (circular, triangular, and square cross section and variable cross section tapered micro perforations) are established, and the end correction of acoustic impedance for different micro perforation shapes are optimized. Based on the acoustic electric analogy method, the coupled model of flexible micro-perforated panel absorber considering the vibration of the substrate panel is established, and the Rayleigh-Ritz method is employed to obtain the panel's natural frequencies, while the Spectro-Geometric Method is used to construct the panel's displacement function. The acoustic impedance formula for flexible micro-perforated panel is derived by the modal superposition principle. The semi-analytical results are verified against finite element method results, confirming the accuracy of the semi-analytical model. In addition, the effects of structural parameters (perforation shapes, microporous length, cross-sectional area, perforation ratio and back cavity depth) and boundary conditions on the acoustic absorption coefficients are analyzed and summarized. Finally, an impedance tube test system is designed to measure the sound absorption coefficient of different hole shapes. The experimental results aligned well with the semi-analytical model, proving the accuracy of the proposed approach.