  Dielectric elastomers are an emerging class of highly deformable
electro-active materials employed for electromechanical transduction
technology. For practical applications, the design of such transducers requires
a model accounting for insulation of the active membrane, non-perfectly
compliant behaviour of the electrodes or interaction of the transducer with a
soft actuated body. To this end, a three-layer model, in which the active
membrane is embedded between two soft passive layers, can be formulated. In
this paper, the theory of nonlinear electro-elasticity for heterogeneous soft
dielectrics is used to investigate the electromechanical response of multilayer
electro-active tubes---formed either by the active membrane only (single-layer
tube) or by the coated active membrane (multilayer tube). Numerical results
showing the influence of the mechanical and the geometrical properties of the
soft coating layers on the electromechanical response of the active membrane
are presented for different constraint conditions.
