Finite Element Modeling of Photostrictive Optical Actuators

Abstract

This article reports development of a finite element for analysis of photostrictive thin films. The photostrictive effect can be thought of as a superposition of a bulk photovoltaic effect and the converse piezoelectric effect. Photostrictive materials can produce strain as a result of irradiation from high-intensity light. Neither electric lead wires nor electric circuits are required. Thus, photostrictive actuators are relatively immune from electrical interference. They have potential use in numerous MEMS devices. In this article, the details of the developed photostrictive thin film finite element are given. The element has been implemented in an in-house finite element code. Results of two verification studies are given. A steel simply supported beam with one PLZT actuator bonded on top of the beam was analyzed. The finite element displacement computations for transverse deflection matched the analytical results computed by another author within about 2%. In a second comparison, transverse deflection for a silicon cantilever beam with a PLZT actuator bonded on the whole top surface of the beam was computed. The finite element computations matched the analytical analysis approach of another author within about 1%.