The Propagation Of SH Wave In Piezoelectric Coupled Structure With Imperfect Interface

In this paper, four piezoelectric coupled structures in which the propagation of SH wave are discussed. The dispersive functions are obtained based ont the shear spring model. The influence of imperfect interface and thickness ratio on the first mode of dispersive curve, distribution of mechanical displacement and electric potential in piezoelectric material and elastic material are investigated.Ⅰ:In the structure consisting of piezoelectric-elastic plates, the initial phase veloctiy of the first mode starts at the bulk shear wave of the elastic plate and approachs to the B-G wave in the piezoelectric plate. The thickness ratio has big effect on the the value and initial of the phase velocity. The imperfect interface would decrease the phase velocity and the worse the interface, the more effect on the phase velocity. The displacement and electric potential are sensitive to the thickness ratio and the imperfect interface.Ⅱ:In the structure consisting of an elstic layer and piezoelectric half-space, the initial phase veloctiy of the first mode starts at the B-G wave in the piezoelectric plate and decreases afet the maximum as the interface gets worse. Also the discountinuity of the displacement and electric potential in the interface gets larger as the interface gets worse and sensitive to the wavelength.Ⅲ:In the structure consisting of a piezoelectric layer and elastic half-space, the initial phase veloctiy of the first mode starts at the bulk shear wave of the elastic plate and approachs to the B-G wave in the piezoelectric plate. The phase velocity decreases by the getting worse interface. The electric potential and displacement in the piezoelectrci plate are all sensitive to the defected interface and wavelength.Ⅳ:In the structure consisting of two different piezoelectric plates. Both of the thickness ratio and imperfect interface are effect on the initial phase velocity which increases as the thickness ratio getting bigger. The imperfect interface would increase the phase velocity which distinguishs others becouse the bulk shear wave and the B-G wave in the first plate are bigger than the second plate. The discountinuity of the displacement and electric potential in the interface gets larger as the interface getting worse.Base on the conclusions from these different models, the existence of imperfect interface would change the phase velocity and the more imperfect, the more effect degree obvious. The discontinuty of the mechanical displacement in the structure gets bigger as the defeat interface gets worse. Also the maximum of the electric potential in the electric material is influenced by the imperfect interface. In the two-plate structure, the thickness ratio would make much effect on the the distribution of the electric potential and mechanical displacement as well.