Document Type



Master of Science


Mechanical Engineering

First Adviser

Moored, Keith


Flyers and swimmers flap their wings and fins to propel themselves efficiently over long distances, maneuver in tight spaces and navigate silently to avoid detection by prey. A key element to achieve these amazing feats is the flexibility of their propulsors. While numerous studies have shown that homogeneously flexible wings can enhance force production and efficiency, animals actually have wings with varying flexural rigidity along their chord and span. The goal of this study is to design and develop an experimental setup that would help understand and characterize the force production and energetics of functionally-graded, chordwise flexible wings. A flapping wing composed of a rigid and a flexible region, that define a chordwise gradient in flexural rigidity, is used to model functionally-graded materials. By varying the ratio of the lengths of the rigid to flexible regions, the flexural rigidity of the flexible region, and the flapping frequency, the thrust production of a functionally-graded wing is directly measured. An unsteady force and torque measurement system is developed to measure the lift/drag forces and power consumption during flapping wing flight in wind tunnel. A novel vacuum chamber apparatus is developed to be used in conjunction with the wind tunnel measurements to reliably measure the aerodynamic power input and the propulsive efficiency.