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Proceedings Paper

Radially expanding mechanism for dielectric elastomers
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Paper Abstract

Dielectric elastomer actuators (DEAs) offer numerous benefits as high displacement smart material actuators. The output of a DEA film is typically characterised by a large area expansion and a smaller transverse displacement. Consequently, their application is often limited by difficulties in resolving area expansion strain into a usable output. Certain DEAs also require pre-strain in order to achieve optimal performance. In this paper, Hoberman's radially expanding mechanism is used to form a novel DEA structure. The mechanism is composed of a number of repeating angulated scissor-links which resolve area expansion into a uniaxial displacement and have intrinsic pre-straining capabilities. This allows the Hoberman mechanism to be exploited as an actuator or as a pre-straining device. The stress distribution induced in the elastomer film when the mechanism is expanded was analysed using photoelasticity, which showed a 6 segment mechanism produces a significantly more uniform strain pattern compared to 4 segments. Prototype DEA mechanisms demonstrated that the Hoberman linkage does resolve area expansion strain into a uniaxial displacement (which can be linear or rotary) at the cost of mechanical friction losses. The 4 segment DEA prototype produced a maximum stroke of 3.13 mm (6.88% planar strain) with a tensile load of 1.46 N. The 6 segment DEA prototype demonstrated improved performance with a maximum stroke of 4.52 mm (7.51% planar strain) and a maximum rotation of 4.98°.

Paper Details

Date Published: 9 April 2010
PDF: 11 pages
Proc. SPIE 7642, Electroactive Polymer Actuators and Devices (EAPAD) 2010, 76420P (9 April 2010); doi: 10.1117/12.847563
Show Author Affiliations
A. T. Conn, Univ. of Bristol (United Kingdom)
J. M. Rossiter, Univ. of Bristol (United Kingdom)

Published in SPIE Proceedings Vol. 7642:
Electroactive Polymer Actuators and Devices (EAPAD) 2010
Yoseph Bar-Cohen, Editor(s)

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