In this paper, transient response analysis of a circular sandwich plate with a functionally graded material (FGM) central disk and two piezoelectric layers is presented. Material properties of the FGM central disk for the circular sandwich plate are assumed to vary through the structural thickness according to a power law and the Poisson’s ratio is assumed as the same constant. Based on the first-order shear deformation theory and geometric nonlinear relationship, the nonlinear motion equations of the circular sandwich plate are formulated by using the Hamilton’s variational principle, then combining with the boundary and initial conditions, the whole problem is solved by adopting the finite difference method, Newmark method and iterative method. Numerical results are presented to illustrate that the volume fraction index, geometric parameters, mechanical and electrical loads have a great influence on transient response of the circular sandwich plate.

Within the framework of linear piezoelectricity, the problem of two collinear electrically dielectric cracks in a piezoelectric layer is investigated under inplane electro-mechanical loadings. The energetically consistent crack-face boundary conditions are utilized to address the effects of a dielectric inside the cracks on the crack growth. The Fourier transform technique is applied to solve the boundary-value problem. Under the consideration of two-case electromechanical loadings, the electroelastic fields near the inner and outer crack tips are obtained through the Lobatto-Chebyshev collocation method. The special case of two collinear energetically consistent cracks in an infinite piezoelectric solid is analyzed and the closed-form solutions of the crack-tip electroelastic fields are further determined. Numerical results show the variations of stress intensity factors and energy release rates near the inner and outer crack tips on the applied electric fields, the geometry of cracks and the width of the piezoelectric layer in graphics. The observations reveal that the stress intensity factors are dependent not only on the adopted crack-face boundary conditions, but also on the applied mechanical loading.