Optimization of geometric parameters of the standardized multilayer microperforated panel with finite dimension.

Standardized multilayer microperforated panel fabricated by laser beam machining of the spring steel was proposed for noise reduction in this study. Geometric parameters of the standardized multilayer microperforated panel, which include diameter of the hole, thickness of the panel, distance between the neighbor holes, and length of the cavity, were optimized for the better sound absorption performance. Sound absorption coefficient of the standardized multilayer microperforated panel was theoretically modeled based on the Maa's theory. The optimization of geometric parameters of the standardized multilayer microperforated panel was obtained by the Cuckoo search algorithm, and the finite dimension of 30 mm was treated as the additional constraint condition. Preliminary verification of the obtained optimal parameters was conducted through the constructed finite element simulation model. Actual sound absorption coefficients of the standardized multilayer microperforated panels with layer number of 1 to 4 were measured by standing wave method, which were consistent with theoretical data and simulation data, and the corresponding average values in the frequency range of 100--6000 Hz were 57.45%, 70.85%, 71.99%, and 72.28%, respectively. By theoretical modeling, parameter optimization, simulation, and experimental validation, an effective method was proposed to develop practical sound absorbers, which would promote their applications in noise reduction. [ABSTRACT FROM AUTHOR]