REFINED SHEAR DEFORMATION-THEORY OF LAMINATED SHELLS

This paper establishes a refined approach for analyzing the effect of shear deformation in thick laminated anisotropic shells using a mixed formulation based on the functional proposed by Jing and Liao. The displacement field uses a zigzag function in addition to the Reissner-Mindlin type in-plane displacements and a constant transverse deflection. The effect of transverse shear deformation is included through an independently assumed transverse shear stress field. The initial curvature effect, which should not be neglected in thick shells, is included in the strain-displacement relations, stress resultants, and the assumed shear stress field. The governing equations are obtained by taking variations of the functional with respect to the displacements and transverse shear. The equations of motion of a general shell are given. Typical examples of thick laminated cross-ply cylindrical panels under cylindrical bending are given to illustrate the accuracy of the present refinement. From the examples investigated, it is concluded that the present theory can supply, with only seven equations, reasonably good results.