M.S. Thesis Presentation by David Hopkinson
Thursday, July 10, 2003

(Dr. Christopher Lynch, advisor)

"Development of Stress Gradient Enhanced Piezoelectric Unimorph Actuator Composites"


The purpose of this study was to develop manufacturing techniques to produce reliable piezoelectric unimorph actuators made from composite materials, as well as to characterize and model them. These actuators consist of a piezoelectric plate that is sandwiched between two composite layers with dissimilar coefficients of thermal expansion, causing them to curve after curing. When an electric field is applied to the actuator, the piezoelectric plate expands or contracts and the non-piezoelectric subtrate resists this motion, causing the actuator to displace in a bending motion. As part of this study, innovative unimorph designs were manufactured and tested, such as brickwork actuators and single crystal actuators. Brickwork actuators use multiple piezoelectric plates instead of a single plate, and are well suited to large scale applications such as deforming the shape of an entire airplane wing. Single crystal actuators use single crystal piezoelectric plates that have a much higher piezoelectric strain response than conventional ceramic plates. The stress distribution, strain distribution, and curvature of the actuators were modeled using classical lamination theory, which included piezoelectric effects.