Uni-axial reinforced dielectric elastomer actuators with embedded 3D printed fibers

Dielectric elastomer actuators (DEAs) can be described as compliant capacitors formed by a dielectric elastomer film sandwiched between two electrodes. An applied voltage results in a compressive Maxwell stress, a thickness reduction and thus an expansion in the other dimensions. In order to favor large uni-axial deformations, it is predicted that DEAs ought to be constrained in the other direction. This can be achieved by reinforcing the DEA with unidirectional fibers. In this paper, the behavior of uni-axial fiber-reinforced DEAs is established and the proposed model innovates by taking into consideration the fiber properties such as their Young's modulus and dimensions, and is characterized by transversely isotropic models. A novel fabrication process is then presented for reinforced DEAs by using 3D printed fibers with four different materials, namely Nylon, PETG, ABS and PLA, and different coverages of fibers are considered. Fiber reinforcement is shown to increase uni-axial strain up to 75% in the manufactured DEAs when compared to traditional DEAs. This behavior corresponds to the one predicted by the proposed model.