Isometric Stress Analysis and Current-Voltage Characteristics of Some Nanoclay Dielectric Elastomer Compounds

The electromechanical properties of elastomer material change when different levels of stretching are applied to the elastomer film. The generated stress and expansion of the EAP material depend on the electric field across the material and its relative permeability. Some of the best known commercial dielectric elastomer materials are based on acrylic elastomers, e.g. 3M VHB 4910 or 4905 adhesive tape. In this work, the VHB 4910 tape was used as a reference material for different types of acrylic nanoclay compound materials. These new type of nanoclay elastomer compounds were tested because the addition of clay into the elastomer was assumed to increase its actuating performance. Different voltage and pre-stretching levels were used in the measurements. Current-voltage characteristics and isometric stress measurements were used to study the energy efficiency, frequency dependent behavior, reactivity and isometric stress performance of the EAP materials. Based on the electromechanical characterization and material properties, a general hyperelastic material model was developed. According to the preliminary tests, the nanoclay compound seems to be a bit stiffer than VHB 4910 resulting in a greater isometric stress response.