Experimental investigation of an active twist model rotor blade with a low voltage actuation system

Abstract

Smart materials that are directly embedded in the rotor blade structure are an attractive concept for active blade control. A promising approach is the use of anisotropic piezoelectric strain actuators embedded in the rotor blade skin. Especially in Europe and the US this concept has been intensively investigated over the past years. A major drawback of all configurations studied so far is the high operation voltage of up to 2,000V of state of the art piezoelectric actuators. Within the Green Rotorcraft Project of the European Joint Technology Initiative Clean Sky, a new approach with a low voltage piezoelectric actuation system is investigated to demonstrate the feasibility of this technology.A first major step in this direction was completed by conducting a centrifugal test with a model rotor blade. The objective of the centrifugal test was to demonstrate the performance of the actuation system and the structural concept under centrifugal loads by showing that the expected twist deformation can be achieved at the nominal rotation speed and different actuation frequencies.It was demonstrated that the new actuation system is capable of operating under representative centrifugal loads. In comparison to state-of-the-art actuators (operation voltage 500V to +1500V) the new actuation system (operation voltage −20V to 120V) exhibits higher active twist performance per active area.

Design and Experimental Characterization of an Actuation System for Flow Control of an Internally Blown Coanda Flap

“…For piezoceramic patch actuators, only the longitudinal (d33-effect) and the transversal (d31-effect) effect are used for technically relevant applications [15]. The arrangement of the electrodes determines which effect will be used.…”

“…Due to this design, the electrical fields are not very homogenous. This has a direct impact on the minimum electrode distance and hence on the For piezoceramic patch actuators, only the longitudinal (d 33 -effect) and the transversal (d 31 -effect) effect are used for technically relevant applications [15]. The arrangement of the electrodes determines which effect will be used.…”

A review on electroactive polymers development for aerospace applications

“…The potential ink-jet printing of EAPs is a low-cost fabrication technique that would offer accuracy and reliability as well as the availability to distribute them over a wide surface, a further advantage that led to the choice of their use (Aschwanden and Stemmer, 2007;Kudva, 2004). In addition, the design of an actively conformable rotor airfoil that can change its shape (thickness and camber) as it traverses around the azimuth is being supported by the National Rotorcraft Technology Center (Bar-Cohen et al, 1999;Janker et al, 2006;Scheller et al, 2011Scheller et al, , 2015Wierach et al, 2013Wierach et al, , 2015.…”