The effective characteristics and electroelastic state of active composite elements

For rods in which the piezoelectric and elastic layers are perpendicular to the rod axis and the lamination has a periodic structure, formulae for the effective characteristics of inhomogeneous material are obtained and the equations that describe the electroelastic state are constructed by the asymptotic method of homogenization. Such active composite elements are known as stacks. As an example, the electroelastic state of stacks executing forced harmonic vibrations under the action of an electrical load is calculated, the effective characteristics of material are found, and both the slowly varying state described by the rod theory and the rapidly varying state caused by the inhomogeneity of the layered structure are calculated. The effect of the thickness of weak adhesive layers on the electromechanical coupling coefficient, characterizing the stacks as energy convertors, is investigated.