Sebastian Liska, Pratt Fellow, Envisions Planes on Folded Wings

January 30, 2008

Pratt Undergraduate Research Fellow Sebastian Liska imagines a day when airplane wings might fold themselves up during flight, not unlike the flexible wings of a bird. That quality would give planes the adaptability to complete complicated, multitask missions.

Sebastian Liska"You might enhance fuel efficiency with extended wings and increase maneuverability with shorter wings," Liska said. "As you change configurations, the plane would become more stable and efficient for particular conditions."

Liska is working in the laboratory of William Holland Hall Professor of Mechanical Engineering and Materials Science Earl Dowell to develop a model of the folding wings to understand how they might actually behave in flight.

Most analysis done on airplane wings and similar problems uses finite element analysis, he explained, meaning that the wing or other structure is divided up into small pieces. But Liska said his project is unique in that it seeks to develop a reduced-order continuum model of folded wings.

In the reduced-order continuum method, he said, "you reduce the computational cost compared to traditional finite element methods. You look at just a few of the dominant modes of motion and combine them to get a fairly accurate picture. For me, this provides a more intuitive view of what is physically happening."

His research falls into the broader field of aeroelasticity. "Aeroelasticity is used to describe how a structure's inertial and elastic forces are coupled with its aerodynamic forces," Liska said. "It's a tripod of forces. You can look at all three to get a clear picture of what's going on with a structure," whether it's an airplane wing or a tall building.

As a double major in mechanical engineering and physics, Liska said he is fascinated by fluid dynamics and structural dynamics. In his work in Dowell's laboratory, he said, "I am constantly amazed by how the two interact."

Engineer in the Making

While growing up in Guatemala, Liska attended an American school taught half in English and half in Spanish. There, he was taught by American professors, getting exposure not only to the language but also to the culture.

His interest in science and engineering also started early. "It's what I'm good at and what I like doing," he said.

When it came time to consider colleges, he found out about Duke through its rankings and from the parents of some of his friends who had gone to Duke many years earlier. "It was a long time ago, but they loved it and encouraged me to visit." Once he did, he found that he appreciated Duke's academic strength in what he calls a less stressful environment.

Liska's early interest in structural dynamics led him first to the civil and environmental engineering and economics departments as a freshman at Duke. But he soon realized that his interests and academic ambitions might be better suited to mechanical engineering and physics.

After conducting some research in a physics laboratory one summer, Liska decided he would apply to be a Pratt Fellow—an excellent introduction to the work he hopes to pursue as a graduate student in an engineering field.

Liska is president of the engineering honor society Tau Beta Pi and vice-president of the physics honor society Sigma Pi Sigma. He is also a Resident Assistant in one of the dormitories, where he said he particularly enjoys interacting with others. During his spare time, he enjoys tutoring his peers in math and physics. "I find it relaxing to help others, and I enjoy seeing how others think," he said.