Mechanical Modelling and Stress-Strain Prediction of Electroactive Polymer-Based Capacitive Sensor under Multiaxial Loads using Uniaxial Tensile Data

Abstract

In this paper, mechanical modelling and stress-strain prediction of the ionic type of electroactive polymer (EAP) based capacitive strain sensor under multiaxial loading has been performed using uniaxial tensile data. A highly stretchable sensor with >400 % strain was fabricated using Styrene-ethylene-butylene-styrene (SEBS) rubber and Dodecyl benzene sulphonic acid (DBSA) doped polyaniline (PANI) composite material as a dielectric film, and carbon grease as top and bottom electrodes. From uniaxial tensile measurements, a three-dimensional constitutive model of the EAP strain sensor was validated. Experimental data obtained from the uniaxial tensile measurement was fitted according to the Ogden-based constitutive mathematical model. For predicting the stress-strain behaviour of the sensor under the multiaxial loads, 2nd term of the Ogden model was demonstrated to fit well with uniaxial tensile data. Such modelling can play a significant role in designing any type of EAP-based sensor for various operations under variable loading conditions.

Keywords

• ionic type of electroactive polymers
• strain sensors
• multiaxial loading
• constitutive modelling
• curve fitting
• uniaxial tensile testing