For his work on characterizing the properties of folding-wing aircraft, mechanical engineering graduate student Ivan Wang was recently awarded a National Defense Science and Engineering Graduate Fellowship from the Department of Defense and the American Society for Engineering Education.

Wang was inspired to pursue this line of research while an undergraduate Pratt Fellow working in the laboratory of Earl Dowell, William Holland Hall Professor and chairman of the Department of Mechanical Engineering and Materials Science.

Wang’s project involves simple modeling of the aeroelastic properties of folding-wing aircraft. Folding-wing aircraft have multiple segments that can rotate relative to each other. This allows the use of the highest-efficiency conformation of the wings for each stage of the aircraft’s mission. This is particularly of interest in military applications where efficiency is a priority.

The model Wang developed predicts the interaction between air flow and wing deformation for these different wing conformations, enabling determination of optimal designs and conformations and the prediction of wing instabilities.

Wang’s models are considered simplified because they do not represent an exact translation of actual wing shape and conditions into a mathematical representation. Rather, Wang’s models represent simplifications of the wings under study.

“For example, instead of modeling a triangular wing, these models would assume instead a rectangular wing shape,” Wang said. “This is done because a formula exists for calculating the aeroelastic deformity of a rectangular wing, whereas more complicated wing shapes do not have analytical solutions for their aeroelastic deformities.”

Nonetheless, Wang said, simplified models ultimately predict the same trends as more complicated models, but at a lower cost and higher efficiency. They also provide a fast and reasonably accurate way to estimate the aeroelastic properties of folding-wing aircraft designs. This would allow accurate appraisals of different designs to be made and taken into account early in the design process: simple models generate enough information to make informed judgments of various designs’ merits with minimal lost time and cost, he explained.

Wang plans to conduct more research and experiments in order to maximize the accuracy of his models. His next steps include incorporating the behavior of a fuselage into the model, requiring experiments to measure forces on a wing that is not simply clamped down in a wind tunnel, since in flight, fuselages and wings are free-moving in the air and not secured in such a way. This will eliminate some of the simplified assumptions from the model, he said.

As part of the fellowship, Wang will receive a $30,000 stipend and tuition for three years creating polymer conjugates.

## Graduate Student Rewarded for Aeroelasticity Work

2012-01-06 10:11