Study on low-frequency sound absorption performance of multilayer-porous resonance structure with different arrangement modes

Abstract Low-frequency noise pollution from transformers has a significant impact on the physical and mental health of workers. In this paper, the resonance structures composed of soft polyurethane foam (PU), aluminum fiber board, porous aluminum, and aluminum micro-perforated plate are constructed. By adjusting the arrangement of different porous materials in the experiment, the acoustic characteristics of different structures are investigated using the impedance tube method. The sound absorption coefficient of composite structure for aluminum perforated plate-porous aluminum-PU reaches 0.93 at a frequency of 327 Hz. The composite structure of aluminum fiber board-PU- aluminum micro-perforated plate has the widest sound absorption range at low frequencies. Thus, the results indicate that the cavities between different porous sound-absorbing materials and the placement positions between different porous sound-absorbing materials have a significant impact on sound absorption performance.