FlexFuture II

In the FlexFuture II project, DLR aims to further develop and industrialize methods that can be used for the aeroelastic analysis of high aspect ratio wings. High aspect ratio wings are a current development trend in both new commercial aircraft and newly developed regional aircraft, both for configurations with conventional propulsion systems and for those with alternative propulsion systems (e.g. (hybrid) electric, hydrogen). Highly stretched wings reduce the induced drag of an aircraft and are thus an important step towards reducing aircraft emissions and therefore an essential step towards climate-neutral flying.

Highly stretched wings are very flexible and pose a number of new challenges. One important point is the question of how increased wing aspect ratio can be achieved without increasing the wing mass compared to a classic design. Such a mass reduction can only be achieved through passive and active load reduction. A further challenge arises because large wing deformations have an effect on the flight mechanics, both statically and dynamically. Requirements for the controller design for flight mechanics and load control can overlap. Large, geometrically non-linear deformations occur in high aspect ratio wings under high loads and influence the results of load and flutter analyses both qualitatively and quantitatively. Conventional design methods assume a linear behavior for the structure as well as analysis methods for loads and aeroelasticity, which is only given for small wing deformations. The development of non-linear methods is necessary here.

All these open points are essential for the design of aircraft with high aspect ratio wings and are evident in the current development processes of aircraft manufacturers. The FlexFuture II project is therefore addressing issues relating to integrated flight and load control as well as aeroelastic modeling of aircraft with high aspect ratio wings.

Objective

Specifically, in FlexFuture II DLR is developing a method ready for use with which the structural dynamic and aeroelastic properties of wings with large, non-linear wing deformations can be simulated quickly and accurately. Furthermore, DLR's modeling capabilities are to be expanded in the individual project to include the integration of flight and load controllers in the design. Finally, validation calculations for the analysis of aircraft with high aspect ratio wings and large, non-linear deformations are to be carried out based on measurement data collected in the project. To this end, DLR is supporting TU Berlin in carrying out wind tunnel tests with the wing of the TU-Flex demonstrator.