Advanced GDQ models and 3D stress recovery in multilayered plates, spherical and double-curved panels subjected to transverse shear loads

The present work shows a systematic comparison between different shell models in the case of static analysis of multilayered composite and sandwich plates and spherical shells. Transverse shear loads are applied on these structures. The behavior through the thickness direction is analyzed in terms of the three displacement components and the six stress components. Such evaluations allow to remark the typical zigzag effect of displacements and the interlaminar continuity conditions in terms of congruence and equilibrium equations in the multilayered plates and shells. The boundary load conditions at the external surfaces are also verified. The proposed 3D models are closed form solutions of 3D shell theories developed in the framework of analytical and semi-analytical approaches for differential equations in the thickness direction. The 2D numerical shell models are classical and refined models developed in both equivalent single layer and layer wise viewpoints. 2D numerical theories are solved by means of the Generalized Differential Quadrature (GDQ) model, which allows general solutions for different boundary conditions, load applications, lamination schemes and geometries. The advantages of this methodology are also clearly shown and discussed for complicated geometries such as doublecurved shells.