At this year’s International Industrial Fair in Brno, experts from the Faculty of Mechanical Engineering at Brno University of Technology will present a new exhibit – a morphing wing segment utilising metamaterials. This is the result of the international BAANG project, on which BUT collaborated with three top European universities: TU Wien, TU Delft, and Imperial College. The prototype demonstrates the possibilities of lightening the structure and improving the flight characteristics of the wing by drawing inspiration from nature, specifically the world of birds.

Morphing refers to the ability of a wing to change its shape depending on the flight mode to achieve optimal performance. This is commonly achieved using movable control surfaces, such as ailerons or flaps. The new approach, based on metamaterial structures, enables a smooth change in the wing’s shape without relying on conventional hinges.

The demonstrator shows two different ways of applying metamaterials – on the leading and trailing edges of the wing. These structures are designed to be flexible in the desired direction but simultaneously rigid enough to transfer the lift force that keeps the aircraft airborne. The entire design was created using a multidisciplinary design optimisation method, which means that knowledge from several technical fields had to be incorporated into the solution.

The development process was not easy. “There were several challenges, both from a technical and management perspective,” recalls researcher Jan Navrátil from the FME Institute of Aerospace Engineering, who was in charge of organising the work, which literally spanned Europe. “The prototype eventually became the final piece, which fortunately turned out well overall. The trailing edge was a huge challenge, where we needed to get the morphable joint working using multidisciplinary design optimisation,” he adds.

Another aviation expert, Pavel Zikmund, describes a similar experience: “The biggest challenge was the design. The production was carried out using fairly standard modelling and engineering techniques, but the design was very complex and took us much longer than expected.”

In addition to the Institute of Aerospace Engineering, other institutes of the Faculty of Mechanical Engineering at Brno University of Technology also participated in the project—specifically, the Institute of Machine and Industrial Design, the Institute of Automation and Computer Science, and the Institute of Solid Mechanics, Mechatronics and Biomechanics. “Foreign partners were also involved in the actual design of the demonstrator, in particular Michael Kofler from TU Wien, who worked on optimisation, and Erik-Jan van Kampen from TU Delft in the role of supervisor,” adds Zikmund.

Cooperation opens up new horizons

Smooth wing morphing offers the possibility of reducing aerodynamic drag and thus fuel consumption. “The improvements are in the order of three per cent, which may not seem like much, but from the perspective of an aircraft fleet, for example, every percentage point represents a significant saving,” explains Navrátil.

At the same time, the technology offers potential beyond aviation. Morphable components could be used, for example, in satellites or other space applications where strength and flexibility need to be combined with the lowest possible weight.

A metamaterial is an artificially created material with properties that do not typically occur in nature. Such materials are made in laboratories and acquire unique electrical, magnetic, optical, or mechanical properties thanks to their special internal structure.

The demonstrator was designed primarily with drones in mind, but its principles can be adapted to other aircraft types in the future. “For laymen, the most interesting thing about our demonstrator will probably be learning about metamaterials and their uses. We actually replaced several parts of the structure with a simple grid printed on a 3D printer, which made the wing lighter and simpler,” Zikmund describes. He adds that the demonstrator is just a prototype and that there is still a long way to go before it can be used in aviation. “We haven’t yet addressed material fatigue, which is critical in aviation. That’s why its use in commercial aircraft is still a long way off. But in theory, the technology could be applied to drones relatively soon,” he adds.

For both researchers, the most significant benefit was international and interdisciplinary cooperation, which was also one of the main goals of the entire project. “The most interesting thing was interacting with experts from other fields who brought their own perspectives to the problem. It opened our eyes,” says Navrátil. According to Zikmund, the project also showed that the key to success is a technical solution and the ability to collaborate effectively. Experts in aviation, mechatronics, materials mechanics, additive technologies, and innovative materials were involved in the research. Six doctoral students and three assistants from BUT were allowed to start their scientific careers with a six-month internship at one of the prestigious universities mentioned above.

More about the project at baang.eu

The project has been funded by European Union Programme Horizon Europe under grant agreement no. 101079091.