Functional dependence of the physical characteristics on irreversible parameters under electromechanical action on the ferroelectric ceramics

The main purpose of the work is to study the functional dependences of the material physical characteristics on the residual parameters of strain and polarization for irreversible process of polarization and strain. The dissipative forces in the inequality for dissipation are presented as a sum of analytical and non-analytical parts. Expansion of the analytical parts in powers of determining parameters provides the differential equations, which, being integrated, yield the unknown functional dependences. Integration constants represent the physical modules of a depolarized state. The tensor components of expansion in powers are determined by using elastic compliance modules, piezoelectric modules, and dielectric constants of two states: thermally depolarized ceramics and ceramics polarized up to saturation. As a result, the constitutive equations for reversible parameters were obtained as linear tensor equations with material elastic, piezoelectric, and dielectric properties representing tensor functions studied above.