Soft electro-elastic materials are an emergent class of materials with electromechanical coupling: electric field induced actuation, strain or pressure sensing, and mechanical energy harvesting. Anisotropic electro-elastic materials consist of an isotropic matrix embedded with oriented fibers or particles that are either electro-passive or active. Here, a new soft electroactive polymer composite consisting of contractile dielectric elastomer fibers is proposed. A series of computational simulations that capture the coupled electromechanical response and account for finite deformations is conducted. The simulations explore the feasibility of enabling novel deformation modes currently unattainable by their isotropic counterparts. In previous work, we proposed a constitutive formulation for isotropic dielectric elastomers under hyperelastic conditions. The model has been shown to be robust under generalized 3D loading, finite deformations, and large electric fields. More recently, constitutive models have been developed for isotropic dielectric elastomers assuming viscoelastic behavior. In this paper, the active fiber network is treated as viscoelastic, and a new anisotropic constitutive model is proposed based on current models of physiological muscle. The model is implemented into the commercial finite element code by employing a user-defined subroutine. The FEM formulation is verified by comparing analytical solutions for uniaxial, biaxial, and simple shear tests. In the new composite, we consider the effect of spatially distributed electric fields and for the first time investigate multi-dimensional electric field activation. Distributed activation via spatially distributed fibers in a pressure-loaded membrane configured for pump-like actuation is demonstrated. We utilize our computational capability to design and optimize complex dielectric elastomer actuator composites configured for electro-hydrostatic coupling.
Yali Li and Nakhiah C. Goulbourne, "Computational simulations of contractile dielectric elastomer composites (Conference Presentation)," Proc. SPIE 10165, Behavior and Mechanics of Multifunctional Materials and Composites 2017, 101651D (Presented at SPIE Smart Structures and Materials + Nondestructive Evaluation and Health Monitoring: March 29, 2017; Published: 10 May 2017); https://doi.org/10.1117/12.2269077.5427412055001.
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