A nonlinear formulation of piezoelectric shells with complete electro-mechanical coupling

A nonlinear piezoelectric shell model capable of accurately expressing the direct and the converse piezoelectric effect is presented. The developed theory is meant to encompass large strains, displacements and rotations that can occur in the shell as a consequence of a complete coupling between the mechanical and the electrical fields. Based on results present in the literature according to which a linear dependence of the electric potential on the shell thickness is not adequate to represent its electrical behavior, a specific structure of the field of admissible displacements is taken into account. Warping functions characterized by an ad-hoc polynomial expansion aimed at expressing their dependence on the shell through-the-thickness coordinate are here considered to describe the shear and the extensional deformability of the shell transverse fibers. Linear constitutive relations for a transversely isotropic continuum are considered. Finally, the governing equations of motion of the shell are obtained via enforcement of the virtual work theorem.