Term of Award

Fall 2011

Degree Name

Master of Science in Applied Engineering (M.S.A.E.)

Document Type and Release Option

Thesis (restricted to Georgia Southern)

Department

Department of Mechanical Engineering

Committee Chair

Rahman Mosfequr

Committee Member 1

Brian L. Vlcek

Committee Member 2

Aniruddha Mitra

Abstract

Micro-Electro-Mechanical-Systems (MEMS) became an emerging technology which allows the integration of micromachined mechanical structures with integrated circuits (IC); this has been a vastly growing area of research and technology during the last two decades. MEMS functional elements are sensors, actuators and miniaturized structures. Photostrictive materials are one of the promising areas of research as an advanced optical actuator for MEMS applications. Photostriction is a phenomenon in which strain is induced in the photostrictive materials due to illumination of high intensity light. Photostrictive effect is a superposition effect of the photovoltaic and converse-piezoelectric effects. Incident light generates a large photovoltage due to the photovoltaic effect, and an induced large voltage produces strain due to the converge-piezoelectric effect on the photostrictive materials. Lanthanum modified lead zirconate titanate (Pb, La) (Zr, Ti) O3 ceramic doped with WO3, called PLZT, is one of the photostrictive ceramics which has an advantage to use as a wireless remote control over traditional actuators. The traditional actuators require wire connections to transmit the control signal; these wires yield noise by the external electromagnetic field. Whereas, PLZT actuators can transmit the control signal without wires and which can eliminate possible noise due to the external electromagnetic field. In this current research the photostrictive effect of a thin PLZT film on a silicon wafer is investigated experimentally and numerically. Experimental transverse deflection of the PLZT optical actuator cantilever beam has been measured for stationary continuous light as well as for pulses of light using an optical chopper at various light intensities and focused locations. Experimental results indicate that transverse deflection increases with the increase of light intensity. And, the maximum transverse deflection at the free end of the cantilever beam for stationary light is three times more than that of for the pulses of light. Finite element modeling results indicate that the magnitude of the transverse deflection of the PLZT beams depend on the PLZT actuator size, locations, light intensity, and boundary conditions. Similar pattern of deflection pattern has been observed from experimental and numerical results for the PLZT cantilever beam.

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