Electromechanical performance of dielectric elastomer composites: Modeling and experimental characterization

Dielectric Elastomer (DE) devices have gained widespread attention in recent years for their ability to generate large, reversible strains in response to electric actuation. However, some DE materials exhibit a viscoelastic nature that detracts from their electromechanical performance in applications requiring precise time-dependent actuation. This study presents an investigation into the feasibility of using multilayered DE composites, comprising commercially available acrylic-based VHB 4905 and natural rubber membranes, to overcome the viscoelastic effects. A comparison of the electromechanical performance of bi-layer and tri-layer DE composites with that of a mono-layer VHB 4910 membrane is carried out through numerical and experimental methods. We present a theoretical model of the DE composite-based bulging actuator, using an energy-based approach and the assumption of homogeneous deformations. The model predicts the time-dependent deflection of the inflated/deflated multilayered DE composites, taking into account the effect of the intervening air column. The predictive capabilities of the model are validated through experiments under both DC and AC operating conditions, and the electromechanical performance of the DE composites is examined for various actuation responses such as resonance, creep, and hysteresis. The bi-layer DE composite is found to be superior in terms of actuation levels, reduced hysteresis, and reduced creep response. The findings of this study hold promise for the development of DE materials with improved actuation capabilities while maintaining dielectric breakdown strength.