Project Title: Passive Noise Control in Rocket Payload Bays
In aerospace structures such as space launch vehicles, external excitation of the fairing by acoustic or structural loads can produce large pressure fluctuations in the internal payload bay, which can damage or destroy the payload. Passive vibration and acoustic absorbers, called vibro-acoustic devices or VADs, have been used experimentally to reduce the levels of noise transmitted through the fairing. The VADs are combined acoustic and structural dynamic absorbers that can be tuned to resonate at specific frequencies, channelling acoustic or structural energy into motion of the absorber, which can then be more easily absorbed. They are essentially a loudspeaker unit attached to the interior surface of the payload bay by a spring.