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Full-Text Articles in Aerospace Engineering
Aeroelastic Energy Harvesting Using A Nonlinear Electromagnetic Oscillator, Katherine Bender, Ndungu Muturi, Alex Spies, Christopher Lee
Aeroelastic Energy Harvesting Using A Nonlinear Electromagnetic Oscillator, Katherine Bender, Ndungu Muturi, Alex Spies, Christopher Lee
Christopher Lee
Results are presented from the design, fabrication and testing of an electromagnetic-inductor device to convert aeroelastic-induced oscillations of an airfoil into electricity. The energy harvester consists of three magnets configured such that the force-displacement relationship can be described by a fifth-degree polynomial. the integration of the harvester into a two-degree-of-freedom, pitch/plunge airfoil system introduces nonlinear stiffness into the plunge direction. This nonlinearity gives rise to limit cycle oscillations which, in turn, are converted to electric power by the harvester. Experimental measurements from wind tunnel tests are compared to predictions of limit cycle response and resulting power generation using a two-degree-of-freedom …
Stall Flutter Measurements From A Two-Degree-Of-Freedom Airfoil With Nonlinear Stiffness, Ndungu Muturi, Alex Spies, Katherine Bender, Christopher Lee
Stall Flutter Measurements From A Two-Degree-Of-Freedom Airfoil With Nonlinear Stiffness, Ndungu Muturi, Alex Spies, Katherine Bender, Christopher Lee
Christopher Lee
Results are presented from an experimental study of stall flutter oscillations from a two-degree-of-freedom, pitch/plunge airfoil system with nonlinear structural stiffness in the plunge direction. With linear (only) structural stiffness, the airfoil system could exhibit a large-pitch-amplitude limit cycle response which is attributed to stall. With the addition of the nonlinear stiffness, the airfoil system could exhibit two classes of limit cycle response: one with low-pitch-amplitude attributed to the structural nonlinearity and one with high-pitch-amplitude attributed to stall. The amplitudes of the limit cycles for cases in which the structurals and aerodynamic nonlinearities co-exist are modulated and remain steady over …
A Perching Landing Gear For A Quadcopter, Elsa Culler, Gray Thomas, Christopher Lee
A Perching Landing Gear For A Quadcopter, Elsa Culler, Gray Thomas, Christopher Lee
Christopher Lee
The design, fabrication, and testing of two prototypes of a landing gear mechanism that would allow a quadcopter to grasp and perch upon a branch-like structure are presented. The prototypes are based upon a snapping-claw mechanism that is triggered on the impact of landing. A complaint claw, fabricated using shape deposition manufacturing techniques, can conform to various shapes and contours of perching structures. Results from flight tests with a commercial off-the-shelf quadcopter and zip line tests are presented which demonstrate the performance of the mechanism.