Optimization design and analysis of the broadband acoustic absorber of the microperforated panel with an interpolated straight tube

The microperforated panel (MPP) structure is widely used in the field of noise reduction. The traditional MPP structure has a fixed absorption peak, and the optimized MPP structure has an improved absorption band, but the frequency range of the absorption is not ideal. For the design of broadband absorption in MPP structures, this paper presents a MPP acoustic absorber structure (N-MH) with an interpolated straight tube (IST) designed for superior broadband acoustic performance. The N-MH structure combines the advantages of the MPP and the embedded necked Helmholtz resonator, as well as having a sub-wavelength thickness of only 60 mm, which is only 1/14th of the wavelength at the first resonant frequency. The N-MH structure is optimized based on the particle swarm optimization (PSO) algorithm. In comparison to traditional microperforated panel structures, the N-MH structure exhibits a significantly broader sound absorption frequency band. Additionally, we thoroughly investigate the factors influencing the mid-low-frequency sound absorption performance of the N-MH structure. Through theoretical prediction, simulation analysis, and experimental testing, it is verified that the N-MH structure has excellent broadband sound absorption characteristics in the frequency interval of 0–2000 Hz, and the percentage of sound absorption bands with absorption coefficients exceeding 0.9 can reach 78.2%.