Using bird bone structure as inspiration, Xin Ning and Sepideh Ebad Sichani, Ph.D. ’26, created a new class of aircraft wing structures – unbound by traditional designs of ribs, spars and stiffeners. The researchers are in the Department of Aerospace Engineering in The Grainger College of Engineering, University of Illinois Urbana-Champaign.

Bird bones are thin and hollow, making them lightweight. But they are also strong enough to withstand strong aerodynamic loads. These two factors make them the perfect inspiration for new aircraft wing designs where both weight and load are important factors.

“If you double the weight, but you only gain 10% increase in your load, that is not an efficient structure because you are adding more weight than the gain in the load,” Ning said. “So, it's always a balance between the maximum load the structure can carry and the material you have.”

The results of the study showed that the bird-bone inspired internal wing framework achieved 48% to 54% improvements in structural efficiency, compared with wings that resembled more traditional internal wing structure with walls.

“A big takeaway is that biology always wins,” Ning said. “We want to look at a learn from the biology to help us design better aircraft structures. And with advanced 3D printers, we can realize the design of bioinspired materials.”

Ning said mimicking nature has become easier to achieve as technology improves.

“The recent advances in 3D printing and additive manufacturing have made it possible to mimic nature and design structures with intricate and complex geometries,” said Ning. “When designing and manufacturing the inside structure of an aircraft wing, we are no longer bound by straight, parallel easy-to-build walls. We can experiment with curved lattice shapes with different angles, mimicking the random structures we see in the natural world.”

Every one of Ning’s major research projects has both computer simulation and experimental components.
“Experiments can help us develop the numerical model, and the numerical model can help us design better structures,” he said. “I really see these two approaches to be tied together, so that is what I've been doing. There is beauty in doing both.

“For example, my student, Sepideh, developed very complicated code. She also developed a manufacturing process, testing methods and processed the data. I believe it is important that students are trained so they have expertise in both experiments and simulations.”
In the numerical work, the researchers compared the weight and load in five groups – five combinations of weighting factors –to minimize wing mass while maximizing load-carrying capacity.

“In numerical simulations, you can explore many more parameters. Ultimately, if you care more about reducing weight, you’ll have very sparse microstructures. There will be more space between the lattices. But if you have a very heavy payload, we used different parameters to emphasize load capacity.”

In the experimental phase of the work, the researchers 3D-printed four wings. Two wings had bird-bone inspired internal structures with more irregular lattice shapes. The other two had internal structures resembling closed-wall foam-like materials.

Each of the two types of internal structures were printed with one of two weighting factors to provide a lattice to wall comparison.

This work was supported by the Office of Naval Research Young Investigator Program, Office of Naval Research Defense University Research Instrumentation Program, Air Force Office of Scientific Research DURIP program, and startup funds from the University of Illinois at Urbana-Champaign. The research was carried out in part in the Advanced Materials Testing and Evaluation Laboratory, which is part of the Materials Research Laboratory Central Research Facilities at the University of Illinois.

The study, “Optimization, additive manufacturing, and testing of bird-bone-inspired materials for aircraft wing designs,” by Sepideh Ebad Sichani and Xin Ning, is published the International Journal of Solids and Structures. DOI: 10.1016/j.ijsolstr.2026.113846