Variable Amplitude Passive Aircraft Vibration and Noise Reduction

Current and emerging Navy turboprop aircraft experience high vibration and noise levels in crew spaces resulting in crew fatigue and reduced work effectiveness. Tuned vibration absorbers (TVAs) are ideally suited for the suppression of unwanted noise and vibration, however, current TVAs only function well at a very narrow band of frequencies and under large amplitude excitations can lead to the mass reaching the travel limits of the device. One method to avoid this issue is with the use of a tuned mass damper (TMD), however TMDs are typically made using viscoelastic materials whose material properties are highly dependent on their operating temperature and thus can lose their tuning in uncertain environments. An alternative damping technique is the use of eddy current dampers, which are non-contact, have no volatile liquids or seals and are nearly insensitive to operating temperature. The proposed research effort would develop variable amplitude TVAs that incorporate tunable eddy current dampers and would provide the DoD with a new technology for the suppression of vibration in turboprop aircraft as well as structures subject to variable environmental conditions and where the dynamic amplitude can be uncertain and extreme.