The general context is to use morphing wings with e.g. droop nose and morphing trailing edge instead of the classical high-lift systems like slats and flaps since these last ones are expensive, complex and heavy, and are therefore not acceptable solutions for the current trends on efficient and green aircrafts. A solution based on morphing wing technology overcomes these limitations. Using a morphing wing concept, which will allow for an increase of the performances of the wing by adapting the wing morphology to the flight condition, is clearly in line with today's expected environmental, energetic and economic requirements.
The specific objective of the DEMMOW project is to investigate an efficient methodology that will be used to develop a high fidelity flexible and non-linear MBS-FEM model of a morphing wing including several structural components (composite box, morphing winglet and wingtip, droop nose and morphing adaptive trailing edge), with flexible parts (compliant mechanisms and flexible skins), kinematic joints, sensors, actuators and control devices included in the model. This model will be confronted to tests results on physical prototypes (conducted in another project) and it will be fine-tuned to conform to the tests. This MBS-FEM model will be a companion of the physical prototype, since it can be used to assess the structural performances and behavior in different configurations (structural integrity and capabilities), the mechanical system functionalities, verify the actuation and control chain, when testing on physical prototypes becomes too expensive and time consuming. Using virtual prototypes besides physical prototypes can increase a lot the competitiveness of the industry as the time to market and the price to develop the product are significantly reduced, and the design can be numerically validated and optimized. Using this digital twin of the physical prototype will allow to reduce significantly the time to go from TRL 4/5 to TRL 6/7 on the morphing wing concept.
Models of the different components were developped, as well as models of the wing for the winglet and wingtip configurations. Comparison to test results were only possible for winglet and wingtip, not mounted on the wing but tested on ground conditions with equivalent concentrated loads. Comparison of model and physical test results for the wingtip showed very good agreement. Regarding the winglet, it was concluded that the test rig should be modeled besides the winglet itself in order to have a close correlation between test and modeling results. Anyway, the winglet model was used to assess its behavior and determine the displacements and internal loads distribution in a loading configuration with variable pressure and moving control surfaces that couldn't be reproduced in laboratory. The digital twin concept then played its role, as expected at the beginning of the DEMMOW project.
