Voltage-driven nonuniform axisymmetric torsion of a tubular dielectric elastomer actuator reinforced with one family of inextensible fibers

Abstract

Abstract Dielectric elastomers (DEs) take the advantage of muscles-like voltage-induced giant deformation and have extensive applications in the fields of soft robots, adaptive optics and bioengineering. In the present work, the finite axisymmetric deformation with torsion of a tubular DE actuator reinforced by one family of inextensible helical fibers is studied by using the membrane theory . The voltage-driven torsional behavior of the DE actuator is caused by the asymmetric reinforcement of helical fibers. By adopting the Mooney-Rivlin elasticity model and the ideal dielectric model and accounting for the inextensibility of the helical fibers, a constitutive model is proposed for the fiber-reinforced DE actuator. Based on these modelling assumptions and considering the equilibrium equations and associated boundary conditions, a boundary value problem for the DE actuator is formulated and also solved numerically. Furthermore, the effects of material parameters and the fiber helical angle as well as mechanical loadings, including the internal pressure, axial force and twist moment, on the voltage-induced torsional behavior of the DE actuator are discussed. The developed model and revealed results are expected to aid the design and fabrication of soft actuators and soft robots.