abstract
- © 2021. All Rights Reserved.A dynamic model to study shear vertical waves in laminated coupled electro-mechanical materials is proposed. The mechanical imperfections at the interface between two materials or phases that constitute an heterogeneous medium are considered. The behavior of vertical transverse waves is analyzed by considering two types of imperfect contact. On the one hand, imperfect contact is taken into account through the motion of layers in the perpendicular direction to the interface. On the other hand, imperfect contact is considered through the motion of layers in a tangential direction to the interface. The layers are coupled through a spring obeying Hooke's law. The degree of imperfection is incorporated through the magnitude of the spring's elastic constant in both scenarios. The stress is proportional to the jump of the displacement vector at the layer interface and to the magnitude of the spring's elastic constant. Dispersion relations for different volumetric fractions of the piezoelectric phase and different degrees of imperfection are obtained. Crossover regions are observed in the dispersion curves. Changes in the oscillation modes could be identified through the material displacements in these regions. Displacements within the composite material, used to describe the nature of the oscillations, are illustrated in some cases. Additionally, the perfect contact case is reproduced by solving the proposed model for large values of the spring's elastic constant, showing a good agreement when compared with the solutions to models proposed by other authors. A comparison between theory and experimental results for the electromechanical coupling factor is presented. Finally, the experimental data for the coupling factor can be better explained by including the degree of imperfection through the model proposed in this work.