Effects of Gyroscopic Phenomena on Tuned Vibration Absorbers Design and Performance

This paper explores the dynamics of rotating Tuned Vibration Absorbers (TVAs), focusing on the phenomena arising from gyroscopic effects. Some products from Leonardo Helicopters (LH) can have a TVA fitted in the rotor mast, counteracting the in-plane vibratory loads of the rotor directly at their source, implying that the absorber rotates with the rotor itself. Although gyroscopic effects are negligible for most of the LH TVAs, specific design choices may have notable impacts on tuning and performance. An analytical model is implemented, demonstrating that the gyroscopic terms influence the dynamics causing a frequency displacement of the anti-resonance evaluated without considering this effect. Additionally, a regression analysis investigates the interplay between this phenomenon and the physics of the system, revealing how to optimize the design to mitigate gyroscopic effects. Finally, the performance of the TVA is analyzed as a coupled problem, showing that the anti-resonance effectiveness is reduced by the orthogonal contribution introduced by the gyroscopic matrix.