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Experimental study and phenomenological modelling of flaw sensitivity of two polymers used as dielectric elastomers

Dilshad Ahmad, Karali Patra, Mokarram Hossain Orcid Logo

Continuum Mechanics and Thermodynamics

Swansea University Author: Mokarram Hossain Orcid Logo

Abstract

The extreme stretching of dielectric elastomers in sensors, actuators and energy harvesting devices is a common phenomenon where the materials are prone to fracture under the influence of flaws and notches. In this work, we have investigated the length of flaw sensitivities of two widely used dielec...

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Published in: Continuum Mechanics and Thermodynamics
ISSN: 0935-1175 1432-0959
Published: 2019
Online Access: Check full text

URI: https://cronfa.swan.ac.uk/Record/cronfa51375
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Abstract: The extreme stretching of dielectric elastomers in sensors, actuators and energy harvesting devices is a common phenomenon where the materials are prone to fracture under the influence of flaws and notches. In this work, we have investigated the length of flaw sensitivities of two widely used dielectric materials, acrylic (VHB) and silicone (Ecoflex) elastomers under a pure shear loading and established that the length of flaw sensitivity of acrylic is almost double than that of silicone. Therefore, the acrylic elastomer is safer to operate for small notches as compared to the silicone material. However, within the flaw-sensitive length, failure stretch, fracture toughness and failure stress are more for Ecoflex than those for VHB. It is found that the failure stretch and the fracture toughness decrease drastically after the length of flaw sensitivities for both materials. Also, the failure stress keeps on decreasing with an increase in notch length for both materials. Afterwards, a simple phenomenological relation is proposed for fitting experimental results under a pure shear loading with only two parameters. The mathematical relation is valid for both the materials and covers the notch sensitivity with a good agreement.
Keywords: Dielectric elastomer, Stretchability, Length of flaw sensitivity, Pure shear, Fracture toughness
College: College of Engineering