Recent developments in smart structures with aeronautical applications

The original version of this paper was presented and distributed as part of the 37th Israel Annual Conference on Aerospace Sciences Proceedings. Without attempting a thorough review of the burgeoning literature, the results of a representative sampling of recent papers dealing with smart materials and structures as actuators in aeronautical systems are summarized here. Their potential for improving performance, handling qualities in a stall, and increasing fatigue life is discussed briefly as requiring relatively slow-acting shape and shape-distribution changes. A similar review is made of applications for improving aeroelastic divergence, flutter instabilities, and tail buffeting on fixed-wing aircraft; and reducing vibrations, improving external acoustics, and providing flight controls for rotating-wing aircraft-all of which require a high-frequency response. The status of some of the most promising developments is noted and the remaining problems are touched on. Two approaches, which have not been given substantial attention elsewhere, are reviewed; these are: developing concentrated, namely nondistributed, piezoelectric actuators in helicoidal configurations, on the one hand, as a way to improve force-deflection output; and using control surfaces purposefully designed to be marginally unstable and stabilized by smart structures, on the other hand, as a means of reducing the force-deflection combinations required of smart-structure actuators.