Membrane-type acoustic resonator for sound control applications

Acoustic resonators are widely used to control sound field inside an enclosure or attenuate a tone from the incident noise in a duct. Traditional resonator designs having fixed geometries and components are only effective at a single narrow frequency band. One shortcoming is that they can hardly provide the tuning ability needed for sound control at varying frequencies, e.g., to deal with blower or engine exhaust noise with changing fan or engine speed. In this study, the use of membrane-type acoustic resonator is investigated, focusing on the fundamental effect of introducing membrane structural resonances into the structure-acoustic coupling. The possible tuning of the resonator for a controllable acoustic performance is also explored. For illustration purpose, an active membrane making use of a pre-stretched dielectric elastomer is incorporated into the resonator design. Results show that the proposed resonator can be tuned with an altering applied voltage for different attenuation characteristics, which may inspire the future development of sound control applications such as novel noise reduction windows or acoustic silencers.