Variable Amplitude Passive Aircraft Vibration and Noise Reduction Navy SBIR FY2016.1 Sol No.: Navy SBIR FY2016.1 Topic No.: N161-021 Topic Title: Variable Amplitude Passive Aircraft Vibration and Noise Reduction Proposal No.: N161-021-0710 Firm: HARP Engineering LLC 3905 Varsity Dr. Ann Arbor, Michigan 48103 Contact: Tim Shankwitz Phone: (480) 205-1202 Web Site: http://www.harpengineering.com Abstract: 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. Benefits: Almost every mechanical, civil or aerospace structure benefits from an effective method of suppressing unwanted vibrations incorporated into its design. A wide range of clever damping devices have been exploited military and industrial applications, however the majority of these damping systems represent mature technologies that are subject to durability concerns and are not well suited for rugged military applications with uncertain environmental conditions and the requirement for maintenance free operation. The use of eddy current damping is ideally suited for the development of a variable amplitude TVA for military aircraft since the technology is insensitivity to variation in temperature, has no volatile liquids or materials that will outgas and is non contact and thus does not experience wear over the device's life. These features make the proposed TVAs ideal for commercialization. Return