  Recently, "Tangential Displacement Normal Normal Stress" (TDNNS) elements
were introduced for small-deformation piezoelectric structures. Benefits of
these ele- ments are that they are free from shear locking in thin structures
and volume locking for nearly incompressible materials. We extend these
elements to the large defor- mation case for electro-active polymers in the
framework of an updated Lagrangian method. We observe that convergence does not
deteriorate as the material becomes nearly incompressible with growing Lam\'e
parameter $\lambda$, and that the discretization of slender structures by flat
volume elements is feasible. The elements are freely available in the open
source software package Netgen/NGSolve.
