An investigation of the resonance properties of rainbow devices

Abstract

In the last fifteen years considerable progress has been made in developing novel materials and devices for electromechanical actuator applications based on a variety of ferroelectric materials. Recently a novel type of high displacement actuator was developed. It is a monolithic, domed, stress-biased wafer consisting of oxide and reduced layers. These actuators are envisioned to be used in a variety of applications for which the knowledge of the resonance modes is essential. In this paper measurements of the resonant modes are compared to the predictions of the finite-element model. A number of low frequency modes were observed and identified as the bending modes. A higher frequency radial mode was determined to be less dependent on the sample dimensions than the bending modes. Effects of the boundary conditions on the resonant modes were modeled and investigated experimentally. For the modeling aspect of the study it was necessary to measure elastic constants, thermal expansion coefficients, and bulk densities of the oxide and reduced portions of the actuator. Experiments to measure these properties were performed and are described.