Characterization of dielectric elastomer actuators based on a visco-hyperelastic film model

Abstract

The electromechanical performance of planar dielectric elastomer (DE) actuators is predicted by applying a novel model for the mechanical behavior of visco-hyperelastic films such as VHB 4910 (manufactured by 3M). The electrostatic pressure was introduced in the film thickness direction to adapt the film model to DE actuators. Moreover, the actuator was embedded in an appropriate electrical supply circuit to account for the electrodynamic effects.
The simulation of the active expansion of a biaxially prestrained, planar DE actuator configuration showed unstable deformation behavior under long-term activation. For activation voltages exceeding a critical level, the active expansion thus became uncontrolled after some time.
The model was also applied to a DE strip actuator configuration under sinusoidal electromechanical excitation. The influence of selected parameters on the overall actuator performance was thereby investigated. While the specific energy density increases with increasing amplitudes of the activation voltage and the stretch ratio, the optimum efficiency is predicted to lie at moderate electromechanical excitations.