ABSTRACT
In this paper, the most widely-investigated models for dielectric breakdown behaviors of elastomers are summarised.
2 MODELS
The dielectric breakdown of materials has been under investigation for a long time since people started to explore the mechanisms of thunderstorms. Much of the previous research focused on solids and the growth of electrical discharge trees (see in Figs. 1 and 2) and there are several models to describe this. Niemeyer, Pietronero and Wiesmann showed that the simplest nontrivial stochastic model (NPW model) of dielectric breakdown leads to a kind of fractal structure, which models the geometrical patterns of surface discharge (Niemeyer et al., 1984). Wiesmann and Zeller introduced and discussed the fractal model of dielectric breakdown which exhibited a breakdown voltage and a region of pre-breakdown
1 INTRODUCTION
Dielectric Elastomer Actuators (DEAs) are a type of deformable capacitor that undergoes large voltage-induced deformations. Due to the Maxwell stress (εE2 for DEAs), the layer of the dielectric elastomer film reduces in thickness and expands in area (Pelrine, 2000). The larger strain and faster response speeds of DEAs compared to traditional actuators are under investigation for a wide range of applications such as artificial muscles, optic and haptic devices (Carpi et al., 2010).
