CYLINDRICAL BENDING OF LAMINATED CYLINDRICAL-SHELLS USING A MODIFIED ZIGZAG THEORY

A relatively simple two-dimensional multilayered shell model is presen ted for predicting both global quantities and stress distributions acr oss the thickness of multilayered thick shells, that is based on a thi rd-order zig-zag approach. As for any zig-zag model, the layerwise kin ematics is accounted for, with the stress continuity conditions at int erfaces met a priori. Moreover, the shell model satisfies the zero tra nsverse shear stress conditions at the upper and lower free surfaces o f the shell, irrespective of the lay-up. By changing the parameters in the displacement model, some higher order shell models are obtained a s particular cases. Although it potentially has a wide range of validi ty, application is limited to cylindrical shell panels in cylindrical bending, a lot of solutions of two-dimensional models based on rather different simplyfying assumptions and the exact three-dimensional elas ticity solution being available for comparisons for this benchmark pro blem. The numerical investigation performed by the present shell model and by the shell models derived from it illustrates the effects of tr ansverse shear modeling and the range of applicability of the simplyfy ing assumptions introduced. The implications of retaining only selecte d terms depending on the radius-to-thickness ratio are focused by comp aring the present solutions to the exact one and to other two-dimensio nal solutions in literature based on rather different simplyfying assu mptions.