Aircraft Lining Panels with Low-Cost Hardware for Active Noise Reduction

Passive structures are augmented with actuators, sensors and control to implement the task of active noise or vibration reduction. Such systems are considered smart because they have advanced functionalities compared to conventional structures. A smart aircraft lining is able to reduce the low-frequency cabin noise induced by tonal or multi-tonal external noise sources. Such noise sources are for example fuel-efficient rotor engines like counter-rotating open rotors. Research on smart systems starts on a laboratory scale by using low-noise sensors and high-performance rapid control prototyping systems. The replacement of such costly and bulky laboratory hardware is one important precondition for the commercialization of smart structures. The increased internal noise, the reduced computational performance and other restrictions of low-cost hardware must be taken into account during the design of a smart system. Experimental results on the noise reduction of a smart lining with low-cost hardware show that a replacement of laboratory hardware will not lead to a loss of performance. The smart lining achieves tonal interior sound pressure level reductions of up to 25 dB with a mass increase of only 2 percent. Even a mass neutral implementation seems possible, if conventional loudspeaker-driven passenger announcements are realized with smart linings.