Morphing resonators for adaptive noise reduction

摘要

Tunable perforate acoustic liners are disclosed using shape memory materials, which allow the acoustic liners to tune for multiple frequencies across a wide range, unlike current designs which are limited to specific frequencies or small ranges. The liner will be initiated through a sensor and feedback loop to monitor the current acoustic environment and initiate geometry change needed to more effectively attenuate engine noise.

主权项

1. A tunable resonant liner device comprising:
at least one housing containing at least one chamber with each chamber having at least one initial resonance frequency, wherein each said chamber is formed by an outer wall, a middle portion and an acoustic opening at the end of the chamber opposite to the middle portion, wherein said acoustic opening has at least one orifice formed therein for allowing a sound to transmit through the acoustic opening into said chamber and wherein said housing contains a second, lower chamber which is formed by said middle portion, said outer wall, and a bottom portion, said middle portion is comprised of selectively flexible material operable to transition from a hard state to a soft state upon application of a stimulus, and wherein, upon application of a stimulus, said selectively flexible material transitions to a soft state and changes the dynamic modulus of the selectively flexible material, thereby changing resonance frequency, acoustic attenuation, acoustic impedance, or combinations thereof for the housing.