  This paper contains a thorough investigation of the performance of
electrically activated layered soft dielectric composite actuators under plane
deformation. Noting that the activation can be induced controlling either the
voltage or the surface charge, the overall behaviour of the system is obtained
via homogenization at large strains taking either the macroscopic electric
field or the macroscopic electric displacement field as independent electrical
variable. The performance of a two-phase composite actuator compared to that of
the homogeneous case is highlighted for few boundary-value problems and for
different values of stiffness and permittivity ratios between constituents
being significant for applications, where the soft matrix is reinforced by a
relatively small volume fraction of a stiff and high-permittivity phase. For
charge-controlled devices, it is shown that some composite layouts admit, on
one hand, the occurrence of pull-in/snap-through instabilities that can be
exploited to design release-actuated systems, on the other, the possibility of
thickening at increasing surface charge density.
