Non-uniformly polarized piezoceramic materials can be used in effective energy harvesting devices. Axisymmetric and plane models of electric elastic bodies were studied using applied theory and finite element method (FEM). Applied theory for devices made of parts with longitudinal and transverse polarization was developed. It was based on bending of electric elastic plates models. Numerical experiments for FEM models were performed in ACELAN package. Applied theory of second order vibrations was introduced.