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Silicone rubber is a common dielectric elastomer material. Actuators made from it show excellent activate properties
including very large strains (up to 380%), high elastic energy densities (up to 3.4 J/g), high efficiency, high responsive
speed, good reliability and durability, etc. When voltage is applied on the compliant electrodes of the dielectric
elastomers silicone rubber, the polymer shrinks along the electric field and expands in the transverse plane. In this paper,
a theoretical analysis is performed on the coupling effects of the mechanical and electric fields. A nonlinear field theory
of deformable dielectrics and hyperelastic theory are adopted to analyze the electromechanical field behavior of these
actuators. Applied elastic strain energy function is obtained from the representative Yeoh model. The electric energy
function involves invariant and variable dielectric constant respectively. Then deduce the constitutive relation for the
dielectric elastomer film actuator based on the selected function. Also the mechanical behavior of the dielectric
elastomer silicone rubber undergoing large free deformation is studied. The constitutive modules of dielectric elastomer
composite under free deformation and restrained deformation are derived. The Barium Titanate (BaTiO3) with high
permittivity was incorporated into the raw silicone to fabricate a new dielectric elastomer, the experimental results that
the elastic modulus and dielectric constant were significantly improved. Finally the Yeoh model was developed to
characterize the elastic behavior of the new dielectric elastomer. The constitutive modules of dielectric elastomer
composite under free deformation and restrained deformation are derived. This is a promising analysis method for the
study of the coupled fields and mechanical properties of the dielectric film actuator.
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