Dielectric elastomer actuators (DEAs) have received a lot of attention in the last decade due to their outstanding actuation strain, high energy density, high degree of freedom, electromechanical coupling and low price. However, modelling of dielectric elastomer actuators is complicated because of time-dependent viscoelasticity, complex geometry, electromechanical coupling and material nonlinearity. For these reasons, just a few research results focusing on modeling of the DEAs have been published.

In this research, taking into account the influence of viscoelasticity, we present a physical and phenomenal based model to characterize the behaviour of a conical DEA made of polydimethylsiloxane. The nonequilibrium thermodynamic framework is used to characterize the mechanical coupling of DEA. Also, free energy and viscoelastic characteristics of DEA are described using the Gent model and the generalized Kelvin model, respectively.

The differential evolution approach is used to find the model parameters based on the experimental data. The model’s validity and generalization are proved by comparing experimental results with model predictions, for both different driving input frequencies and amplitudes. The experimental results demonstrate a high level of agreement with the developed model.