Theory analysis method for the effect of temperature and electrostrictive on the actuation stability of dielectric elastomers

Abstract

Dielectric elastomer (DE) as an electroactive soft material can produce large deformation induced by voltage. Usually, the deformation is limited by various failure modes, which affect the stability of the DE electrical actuation. The previous researches have demonstrated temperature affection on the dielectric constant of DE. In this paper, the mathematical calculation theory for the various unstable DE failure is deduced with the thermoelastic model. The numerical model and analysis result discussed the effects of temperature and electrostriction coefficient on the instability phenomena of DE. The nominal stress deformation changes with the nominal electric displacement on the DE material at different temperatures. The stable working range area encircles by the curves of electromechanical instability (EMI), tension loss (s = 0), electrical breakdown (EB), and tension rupture (λ = λ_R). The results show that the increase of temperature can improve the nominal stress and the nominal electric field of the actuator, which consequently enhances the stability of DE. Simultaneously, the stability of DE can also be improved when the electrostriction coefficient becomes smaller within a certain range. These conclusions have implications for improving the stability of DE electro-deformation.