Mixed Finite Elements for Higher-order Laminated Cylindrical and Spherical Shells

This paper presents a mixed finite element (MFE) formulation for studying the linear static behavior of both thin and relatively thick laminated composite cylindrical and spherical shells. The method employs the Higher Order Shear Deformation Theory to account for cross-section warping due to transverse shear stress. It ensures the stationarity of the system's functional using the Hellinger-Reissner principle. Finite element discretization is accomplished with four-noded quadrilateral two-dimensional elements. The MFE formulation offers the advantage of directly obtaining displacements and stress resultants at the nodes. Comparison and convergence analyses are performed considering various shear functions, boundary conditions, and geometrical configurations.