Frequency response of fiber reinforced DEAs

Dielectric Elastomer Actuators (DEAs) have emerged as versatile and promising devices for a multitude of applications, including soft robotics, haptic interfaces, and artificial muscles. DEAs are an interesting soft actuator technology due to their high energy density, and fast response. They can be described as compliant capacitors composed of a dielectric elastomer film situated between two electrodes. When a voltage is applied, it induces a compressive Maxwell stress, causing a reduction in thickness and thus an expansion in the other dimensions. However, DEAs tend to exhibit limited deformations under uni-axial forces. To overcome this limitation and induce substantial uni-axial deformations, it is suggested that DEAs should be constrained in the other directions. This constraint can be realized by reinforcing the DEA with unidirectional fibers, resulting in strains up to 75% higher for reinforced DEAs than for conventional DEAs. In this paper, the response time of uniaxial fiber-reinforced DEAs is studied, to evaluate the influence of the reinforcement on the frequency response. To that end, uni-axial fiber reinforced DEAs with a silicone dielectric layer are fabricated by embedding 3D printed fibers of different materials onto the actuators. Fused deposition modelling is used by tuning the infill of the printed part, allowing a fast, simple, and accessible fabrication of the fibers. The response time of the actuators is improved with the use of uni-axial fiber reinforced DEAs, as they provide a more rigid structure and less losses, with a decrease of up to 15% in the response time.