Influence of fiber material on actuation and sensing in fiber-reinforced DEAs

Dielectric elastomer actuators (DEAs) are widely studied in soft robotics due to their fast response, high deformability, and flexible design. A typical DEA consists of a pre-stretched elastomer membrane with compliant electrodes on both sides; applying a high voltage induces Maxwell pressure that deforms the elastomer. Strip actuators are a common DEA design because they are simple to fabricate and allow flexible geometry. When combined with a passive fiber reinforcement layer, these actuators become mechanically anisotropic, forming fiber-reinforced DEAs (FRDEAs). FRDEAs enable uniaxial deformation, simplified control, and actuation forces that are independent of actuator aspect ratio. While prior studies have focused on FRDEAs reinforced with conductive silicone-carbon fiber composites, the influence of non-conductive reinforcement fibers has not been thoroughly investigated. This study explores how different fiber materials affect the mechanical and electro-mechanical behavior of FRDEAs, with an emphasis on glass and basalt fibers commonly used in fiber-reinforced plastics. Variations in fiber material alter fiber-matrix adhesion, which influences mechanical behavior. These effects are evaluated through strain measurements and digital image correlation. Because the selected fibers are non-conductive, the resulting electro-mechanical strain behavior deviates from that of previously studied FRDEAs, and is explored in detail here in addition to the electro-mechanical actuation performance.