Date of Award

5-2021

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Aerospace, Physics, and Space Sciences

First Advisor

Razvan Rusovici

Second Advisor

James Brenner

Third Advisor

David Fleming

Abstract

Wing morphing was investigated as an alternative to conventional discrete flight control surfaces to provide aircraft attitude control, performance, and to enhance wing aerodynamic efficiency. A variable camber morphing wing design with 100 cm span and 34 cm chord was proposed for small UAVs operated at low velocity. The proposed morphing wing design generated trailing edge deflections via the combined action of an inner complaint flex core structure and a retractable wing skin. Wing morphing was produced by linear servos that extended and retracted the upper and lower wing skin and produced a controlled deformation of the inner complaint flex core. Five servos actuated the upper wing skin, and five servos actuated the lower wing skin. The quantity of servos required to actuate the wing skin without inducing failure was determined using the maximum strain failure criteria for composites. The maximum power required by each servo was 1 W, the maximum force required by each servo was 70 N, and the maximum actuator stroke required by each servo was 7 mm. The morphing wing could maintain a quasi-seamless profile while in the morphed configuration and non-morphed configuration, except for a 1.5 mm step near the leading edge. The thickness of the compliant flex core structure and retractable wing skin was tailored to achieve trailing edge deflections from -50° to +50° via a multi-objective optimization study. The wing skin was found to be susceptible to buckling under actuation loading, with maximum deformations of 3 mm. The largest stress generated during wing morphing was 450 MPa at 50° trailing edge deflection. A comparative CFD analysis performed at velocities of 10 m/s, 20 m/s, and 30 m/s suggested that the morphing wing generated more lift compared to a non-morphing baseline wing with flap over a limited range of drag coefficients from 0.025 to 0.125. A limited aeroelastic analysis conducted via a one-way fluid-structure interaction revealed that the optimized morphing wing structure experienced small uncommanded trailing edge deformations that did not exceed 2.25 mm and stress that did not exceed 110 MPa when subjected to air loads induced by velocities of 10 m/s, 20 m/s, and 30 m/s.

Download

Share

COinS