MULTI-PHYSICS DESIGN AND MODELING OF 3D PRINTED HYDRAULICALLY AMPLIFIED DIELECTRIC ELASTOMER ACTUATORS WITH LARGE ACTUATION STROKES

This study presents the design and multi-physics finite element analysis of a novel hydraulically amplified dielectric elastomer actuator (HADEA). The design was optimized for additive manufacturing and consists of a hyper-elastic silicone toroidal shell enclosing a dielectric liquid filled chamber and a pair of elastic annular electrodes partially covering the opposing actuator surfaces. Application of voltage on electrodes leads the central region of the HADEA to be compressed due to the induced Maxwell stress. Consequently, the peripheral region of the HADEA is axially expanded by the pressurized dielectric liquid. The finite element modeling and analysis that couples the structural, electrostatic, and fluid-structure interaction effects in the model is presented. We investigated the effect of two geometric parameters, the electrode size relative to the actuator diameter and the height of the actuator, on the actuation stroke of HADEAs. Numerical results showed actuation strains up to 63.1% while maintaining the electrodes' voltage in instrument range. The proposed design shows promising potential for the application of HADEAs in bio-mechanical systems, soft robots, and co-robots capable of human interaction.