Structure design and experimental analysis of a perforated dielectric elastomer sound absorber

A large part of research on membrane mufflers focuses on the sound insulation performance of the membrane, and there is less research on the sound absorption performance of the membrane. In most cases, membrane mufflers only have some narrow absorption peaks in the low frequency band. In this paper, a micro-perforated dielectric elastomer membrane sound absorber is introduced to broaden the sound absorption frequency band of the membrane in the low frequency band. Different initial thickness, perforation aperture, and perforation spacing of the dielectric elastomer membranes were designed and fabricated, and the effect of the variation of the parameters was investigated by testing the sound absorption performance of the structural specimens. It was found that increasing the initial thickness of the membrane, appropriately decreasing the perforation aperture, and appropriately controlling the perforation spacing could improve the sound absorption performance of the structure. And based on the perforated membrane, a ring electrode structure was further designed to realize the electrically adjustable sound absorption frequency of the membrane. After the membrane with the ring electrode structure was perforated in the central region, the sound absorption band of the membrane was broadened significantly, and the applied voltage could realize the electrically adjustable sound absorption performance of the structure in the low frequency band.