Microstructural Dielectric Elastomer Actuator with Uniaxial In-Plane Contraction

• Main Authors: Shih-Chieh Lin, 林士傑
• Other Authors: 張培仁
• Format: Others
• Language: en_US
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/95566805464799246820

博士 === 國立臺灣大學 === 應用力學研究所 === 101 === In this dissertation, a micromachined dielectric elastomer actuator with uniaxial in-plane contraction was proposed. The modeling, fabrication and testing of the actuator were carried out. The proposed dielectric elastomer actuator was made of polymers by micro-electro-mechanical systems (MEMS) technique. When a bias voltage was applied, the resulting electrostatic force compressed the dielectric elastomer which then shrank in area due to its embedded microstructures. This actuator consisted of two electrode layers, two flexible layers and a microstructural layer, respectively. The microstructural layer possessed the grating patterns which served as the spacers to define the gap between the upper and the bottom flexible layers. The grating patterns also determined the direction of the in-plane contraction. When the applied electrostatic force pulled together the bottom and the upper flexible layers, these two layers bent inwardly and shortened the distance between the spacers. Two actuation types of actuators were demonstrated, which were bending and contraction actuation behaviors. The design of the bending actuation was demonstrated utilizing the asymmetric thickness design of the flexible layers, on the other hand, the actuator with symmetric thickness design of the flexible layers shows contraction actuation. The geometric effects for the actuation behavior of the proposed dielectric elastomer actuator were discussed, including thickness of the flexible layer and the distance between the neighboring spaces. The actuator with bending actuation was measured by CCD camera to detect the free-end deflection, and the actuator with contraction actuation was measured by Laser detector and microbalance to obtain the contraction length and the actuation force. The analytical solution for the deflection of the proposed dielectric elastomer actuator subject to electrostatic loads is derived based on the Euler’s beam model and energy method. Then one can use the closed form solution of the deflection to derive the contraction length and actuation force of the proposed dielectric elastomer actuator. Furthermore, these solution results were verified by ANSYS simulation and experiment. The microstructural dielectric elastomer actuators with lightweight, flexible and relative low driving voltage compared to the conventional dielectric elastomer actuator were designed and demonstrated. Because of these characteristics, the actuators could further be used as artificial muscle.