Characterization of dielectric elastomer actuators based on a hyperelastic film model

The focus of this paper is on the energy characterization of dielectric elastomer (DE) actuators under quasi-static activation cycles. To this end, a simple model covering the basic mechanical effects of hyperelastic dielectric elastomer films was introduced and fitted to the experimental behavior of the widely used dielectric film VHB 4910 in a uniaxial tensile test. The film model was then applied to planar DE actuators by introducing the electromechanical coupling of the electrodes to the film. The evaluation of this system permitted the characterization of the inner force equilibrium states of planar DE actuators under activation with either constant charge or constant voltage. In a second step, a quasi-static activation cycle of an idealized DE strip actuator with uniaxial prestrain was simulated. The configuration was evaluated regarding the characteristics of the specific work output per cycle as well as the overall electromechanical efficiency for various activation voltage levels and different prestrain levels.