Electromechanical deformation of dielectric elastomer in two types of pre-stretch

¹ Department of Mechanical Engineering, Xi'an Jiaotong University - 28 Xianing Road, Xi'an, 710049, China
² State Key Laboratory for Strength and Vibration of Mechanical Structures, Xi'an Jiaotong University Xi'an, 710049, China
³ National key Laboratory of Aerodynamics Design and Research, Northwestern Polytechnical University Xi'an, 710072, China

^(a) liboxjtu@mail.xjtu.edu.cn

Received: 9 April 2014
Accepted: 11 June 2014

Abstract

A pre-stretched dielectric elastomer is capable of large deformation, when subject to voltage. This paper investigates the effect of two types of pre-stretch: by strain and by stress. The difference is compared and discussed using thermodynamics models. The significance of the pre-stretch in actuation is explained by examining the true stress in actuation. Under both pre-stretch strategies, during the actuation, the dielectric elastomer exhibits hysteresis loops due to snap-through but differs in shape and physical quantity. With pre-stretch by strain, the dielectric elastomer features a discontinuous snap in stretch while with the stress the voltage snaps.