Material Modeling and Microstructural Optimization of Dielectric Elastomer Actuators

The modeling and 3D numerical implementation of dielectric elastomer actuators are discussed in this work. The electromechanical coupling for the actuator is realized via the Maxwell stress in the mechanical balance. In this nonlinear numerical problem the consistent tangent matrix, which is used for the Newton iterations, is described in detail. The operational curve of a homogeneous capacitor structure is compared to analytical solutions by implementing the Neo-Hooke and the Yeoh material model in the numerical simulations respectively. In this simulations the instability aspects of this type of structure is discussed. Furthermore the optimization of the operational curve is analyzed for both material models through the consideration of inclusion materials in the elastomer structure. Piezoceramic and a soft material inclusions with a fiber and a spherical geometry are considered. The results show the capability of improving the operational curves of the actuator with these inhomogeneities