1st International Conference on Innovations in Natural Science and Engineering, Famagusta, Cyprus (Kktc), 03 January 2018, pp.25
This work studies the 3D buckling delamination problem around the interface band cracks which are in the PZT/Metal/PZT sandwich rectangular thick plate within the scope of the piecewise homogeneous body model by utilizing the so-called 3D linearized theory of stability loss for piezoelectric materials . It is assumed that the plate is mechanically simply supported at all the lateral edges of the rectangular plate and also closed-circuit conditions with respect to the electric potential along all the lateral edges as well as the face planes of PZT layers. Moreover, it is assumed that on the opposite two ends of the plate which are parallel to the band cracks’ front, uniformly distributed normal compressive mechanical forces act. It is determine the critical values of these forces due to evalution of the crack opening within the initial imperfection criterion . Formulation of the considered buckling delamination problems are made in the framework of the exact equations of 3D linearized electro-elasticity theory for piezoelectric materials. The solution to the corresponding boundary value problems is made numerically by employing the 3D FEM. Numerical results retated to the influence of the problem parametres such as electro-elastic constants, ratios of the crack length to the plate length etc., and as well as related to the influence of the coupling effect between the electrical and mechanical fields on the critical forces are presented and discussed. In particular, it is established that the piezoelectrical properties of the face layers' material of the considered sandwich rectangular plate increase the critical values of the buckling forces. This can be explained with the “stiffening” effect of the piezoelectric materials. Moreover, the comparison of the obtained results with the corresponding ones given in the paper  in which the open-circuit condition is satisfied on the face planes of the piezoelectric layers, shows the critical forces obtained in the present case are less than corresponding ones obtained in the paper . Moreover, the analysis of the obtained numerical results shows that they agree in the qualitative sense with the corresponding ones obtained in the papers [4, 5] in which the plane-strain state and axisymmetric buckling delamination problems are investigated.