Meeting Abstract
As the variety of uses for aircraft increases, so too does the need for flight structures that are robust and adaptable to unforeseen circumstances. Birds achieve this adaptability to variable flight conditions by actively changing wing shape (“wing morphing”) during everyday flight. By rearranging flexible components, such as feathers, relative to each other, changes to wing shape may also modulate the wing’s mechanical properties, and thus aeroelastic responses and flight performance. We first sought to determine how changes to wing shape affect local wing stiffness in anesthetized pigeons (Columba livia). In each of two extreme wing positions (extended and folded), we calculated stiffness by measuring the force resisting an oscillatory position change actuated near the base of select flight feathers. To test whether stiffness is more significantly affected in some areas of the wing during morphing, stiffness measurements were acquired near a distally-located leading-edge primary flight feather (P9) and a proximally-located flight feather near the wrist joint (P1). We then performed these measurements with and without the neighboring feathers present to test whether changes in stiffness were due to feather-feather interaction. We found that wing folding changes stiffness most significantly in areas near the wrist joint through an increase in feather-feather interaction. The effects of these changes in wing stiffness on fluid-structure responses and aerodynamic performance were then evaluated using computational fluid modeling. Our findings provide insight in the design of multi-component structures capable of modulating aeroelastic responses, thus increasing the performance envelope of aircraft.
