Materials and actuators for the shape control of structures

摘要

Smart materials and actuators meet a noticeable infatuation for the shape control of aerodynamic surfaces. This interest is borne as well to reduced scale where space is limited for the machining of models allowing to demonstrate the merits of some advanced concepts as to full scale prototypes, where these novative mechanisms are supposed to replace advantageously hydraulic or classical electro-magnetic solutions. These new devices are even supposed to provide in some cases several benefits for integrity improvement of the structure itself. The extrapolation from one to the other is nevertheless not straigth forward and must take into account the distinct specifications if only the avionability constraints and the cost. If bulk and multilayered electro-active materials and integrated adaptive systems issued from them are convenient for dynamic control, shape memory alloys are only suitable for slow but quite significant geometry changes. After a brief survey of the most outstanding properties, the availability and the limitations of usual materials, actuators and electronical controllers, easily provisionable on the market, the paper deals with some technological applications experimented on models. The subjects investigated concern the flap deflection, the twist of rotor blades and the swelling of a wing profile. The last part of presentation points out some fast started-up and economical developments, to promote these actuators in the near term in order to compensate topical deficiencies, and first actions already undertaken to this end.