Layer-wise mixed models for accurate vibrations analysis of multilayered plates

This paper presents the dynamic analysis of multilayered plates using layer-wise mixed theories. With respect to existing two-dimensional theories at the displacement formulated, the proposed models a priori fulfill the continuity of transverse shear and normal stress components at each interface between two adjacent layers. A Reissner's mixed variational equation is employed to derive the differential equations, in terms of the introduced stress and displacement variables, that govern the dynamic. equilibrium and compatibility of each layer. The continuity conditions at the interfaces are used to write corresponding equations at multilayered level. Related standard displacement formulations, based on the principle of virtual displacements, are given for comparison purposes. Numerical results are presented for the free-vibration response (fundamental and higher order frequencies are calculated) of symmetrically and unsymmetrically laminated cross-ply plates. Several comparisons to three-dimensional elasticity analysis and to some available results, related to bath layer-wise and equivalent single-layer theories, have shown that the presented mired models: (1) match the exact three-dimensional results very well and (2) lead to a better description in comparison to results related to other available analysis.