The analytical and experimental studies of a circular multi-layered annular piezoelectric actuator

• Main Authors: Yu-Kai Chen, 陳裕楷
• Other Authors: I-En Lin
• Format: Others
• Language: zh-TW
• Published: 2009
• Online Access: http://ndltd.ncl.edu.tw/handle/hb8nj7

碩士 === 國立虎尾科技大學 === 機械與機電工程研究所 === 97 === Piezoelectric materials have been used in many Micro-Electro-Mechanical Systems (MEMS) for actuation, particularly in micropumps. Of several configurations used in micropumps, the circular disk is the most popular. In many cases, the unimorphs consisting of a piezoelectric layer sandwiched between two metallic electrodes and passive layers of various materials are used. This configuration has a predominant d31 piezoelectric coefficient and therefore excitation in the transverse direction between the two electrodes produces a strain in the radial direction. The d31 piezoelectric coefficient results in deflection of the disk if the circular edges are clamped. This deflection is used to generate the pumping action in the MEMS style micropumps, or provides the kinematic mechanism in inkjet module. The circular annular piezoelectric actuator is particularly used in the fluid droplet ejector or oxygen bubble generator since the nano-scale nozzle plate can be integrated in the orifice region. This thesis presents closed form analytical expressions for static deflections of a circular annular piezoelectric actuator with multiple material layers in terms of the applied voltage and pressure loadings, the actuator geometry and the material properties. The expressions are validated both numerically via finite element analysis and experimentally deflection measurements. The influences of packaging geometries and residual stresses possibly resultant from fabrication on the transverse deflection are investigated in this work.