Theoretical and experimental study on sound absorption performance of Al₂O₃-polyurethane foam and microperforated plate composite structure

Low-frequency noise pollution in substations has a significant impact on the physical and mental health of workers. Reduction low-frequency is an urgent problem to solve for researchers. In this paper, different structures Al 2 O 3 -polyurethane composites micro-perforated plate were constructed, effects cavity depth, perforated plate, foam position sound absorption properties comprehensively investigated. The results showed that arrangement resonance structure two most important factors affecting performance. When wave passed through plexiglass plate–cavity–composites foam–perforated turn, peak coefficient was located ultra-low frequency range. Meantime, simulation study friction between air column wall can consume energy achieve absorption.