Novel, High-Authority Flap Actuation Concepts using Single Crystal Stacks

Piezoelectric flap actuators have exhibited inadequate levels of stroke and/or force required to produce angles of rotation in excess of ±5° at 40 Hz. Single crystals represent a revolutionary advance in piezoelectric technology. Because crystal properties are significantly different than those of ceramic, crystal actuators require amplification techniques that are specifically tailored to crystal behavior. This proposal describes a high authority flap actuator concept for helicopter vibration control and noise suppression that will be designed for single crystal stack actuators. Invercon will evaluate the feasibility of using crystals together with two complimentary flap actuation concepts. The first is a high-displacement buckling beam actuator concept, which is well-suited for single crystal stack actuation. The second is a general method to mechanically tune and electrically tailor any electromechanical actuator for high robustness and authority at resonance. Buckling beam actuators should dramatically outperform state-of-the-art flap actuators, with the capability of displacing a 36" flap 9.5? at 40 Hz rotating at 400 RPM. Such actuators are simpler and significantly lighter than existing designs, as well. The Phase I will investigate the feasibility of using a buckling beam flap and crystal actuation in collaboration with manufacturer TRS Ceramics, Inc and researchers at the Pennsylvania State University.