Overview of the project's results
The SMS project provided the following major results during the first 18 months:
- Efficient actuation systems for the RS and LS prototypes, able to operate at different time and length scales: high-deformation/slow frequency (order of 1Hz) and low deformation/higher-frequency vibrations (order of 500 Hz). The association of both ensured the so-called “hybrid elctroactive morphing”, which is partly bio-inspired from the flight of large span hunting birds. This kind of morphing, applied in the case of the sRS prototype is proven able to considerably increase the aerodynamic performances: by means of camber control, a lift increase of over 10% is obtained. By associating high-camber and optimal higher frequency vibrations in the range of 200-300 Hz together with slight deformation of the near-trailing edge region along 4-5 cm, an order of more 3% lift increase is achieved. Furthermore, a simultaneous decrease of drag of 4-5% is obtained as well as noise sources reduction of order 8%.
These benefits have been realised thanks to two classes of smart electroactive materials (smart actuators): Shape Memory Alloys (SMA) for the high deformations and piezo-actuators of Macro-Fiber Composite type (MFC) ensuring the higher-frequency vibrations, operating in quite moderate amplitudes: fraction of 1 mm. The implementation of the hybrid morphing is a breakthrough of the SMS project.
- Suitable manipulation of the turbulent vortices around the rear part of the wing and in its wake, in order to break down harmful ones and to enhance beneficial vortices thanks to optimal actuations, able to thinning the shear layers and the wake, providing by feedback drag reduction and to lift increase.
-Clear explanation and analysis of the physical mechanisms optimised by the electroactive morphing leading to the aerodynamic performance increase (lift-to-drag-ratio) of order 5 to 10% according to different flight phases: take-off, landing and cruise, thanks to a strong synergy among the Hi-Fi simulations and the aerodynamic experiments.
- Design of the LS prototype (a two-element A320 type wing with its high-lift flap) in full scale, enabled by high-camber morphing capable to bear and to distribute the right aerodynamic forces in full scale conditions. This design has been realised by means of two kinds of actuators: Electromechanical and SMA. The construction of the LS static prototype has been achieved and the construction of its morphing part in respect of these two kinds of actuators is under final realisation.
- Wind tunnel experimental verification achievements for the sRS and the LS prototype in two wind tunnels of test section 70cm and 2,40 m respectively, corresponding to the take-off configurations
- Achievement of economic electrical power supply systems for the morphing: order of a decade of W for the RS prototype and of 50 KW for the LS one, as well as ability of force bearing of order 1,5 t for the LS prototype. Moreover, the added weight on the wing’s structure is quite light comparing to other more heavy systems based on MEMS or conventional hydromechanical actuators.
