Design of diaphragm dielectric elastomer actuators (DEAs) and experimental characterization techniques [article]

Micah Hodgins, Universität Des Saarlandes, Universität Des Saarlandes
Hiermit versichere ich an Eides statt, dass ich die vorliegende Arbeit selbstständig und ohne Benutzung anderer als der angegebenen Hilfsmittel angefertigt habe. Die aus anderen Quellen oder indirekt übernommenen Daten und Konzepte sind unter Angabe der Quelle gekennzeichnet. Die Arbeit wurde bisher weder im In-noch im Ausland in gleicher oder ähnlicher Form in einem Verfahren zur Erlangung eines akademischen Grades vorgelegt. Saarbrücken, Dezember 2016 ABSTRACT Dielectric elastomer (DE)
more » ... cers are a new technology offering many benefits for actuation and sensing devices. This work focuses on DE actuators (or DEAs) which have been shown to exhibit high-strain and high-speed characteristics. Diaphragm DEAs are a type of membrane DEA configured to operate out-of-plane. However, to produce reasonable stroke, membrane DEAs should be pre-stretched with a compliant mechanism. Therefore, the actuator system consists of the DEA and the necessary compliant mechanism. The first focus of this work to investigate how DEA membranes operate as a system and how they can be improved by designing compliant mechanisms which, when coupled with the DEA, give higher performance. Several compliant mechanisms are presented and experimentally compared. A bistable mechanism called a negative-rate bias spring (NBS) is shown to greatly increase the output of the DEA. The second part of this work presents two test devices and techniques for electromechanically characterizing DE membranes. One is a programmable electromagnetic motor to characterize diaphragm DEAs and test them under different loading conditions. The second device is designed to repeatably characterize planar DEs through a tensile test. The work includes a novel technique for obtaining a membrane thickness profile while stretching and/or actuating the DEA. The tester allows for a comparison of material performance parameters which aid in more informed design recommendations for future DEAs. DEDICATION To my beloved wife, Julie BIOGRAPHY Micah William Hodgins was born in South Carolina on April 6, 1986. He graduated from the University of South Carolina-Columbia in May 2008 with a BS in Mechanical Engineering and from North Carolina State University December 2010 with a MS in Mechanical Engineering. Parts of this work have been published in the following papers: Peer-reviewed journal papers: M. Hodgins and S. Seelecke, "Systematic experimental study of pure shear type dielectric elastomer membranes with different electrode and film thicknesses," Smart Mater.
doi:10.22028/d291-23206 fatcat:hmohmvuui5fhpowbhmv2a32vne