A general nonlinear global-local theory for bending and buckling analyses of imperfect cylindrical laminated and sandwich shells under thermomechanical loads

Abstract

The accurate shell theories proposed so far have been calibrated based on linear kinematic relations. Many of them have ignored either the interlaminar stress continuity conditions at the interfaces or the transverse flexibility of the layers. Therefore, the available shell theories may encounter accuracy problems when analyzing the nonlinear behaviors, especially for sandwich shells with soft cores. Moreover, almost all of the available shell theories have been proposed employing the Love-Timoshenko assumption. Ideas of the previous global-local plate theory of the author are extended to develop the present nonlinear high-order global-local shell theory. The present theory has the advantages of: (1) suitability for non-linear analyses, (2) higher accuracy due to satisfying the complete interlaminar kinematic and transverse stress continuity conditions at the layer interfaces under thermo-mechanical loads, employing the exact Green’s strain tensor of the curvilinear coordinates, considering the transverse flexibility, and releasing the Love-Timoshenko assumption, (3) less required computational time due to using the global-local technique and matrix formulations, and (4) capability of investigating the local phenomena. To enhance the accuracy of the results, compatible Hermitian elements are employed. Various comparative examples are included in the present paper to validate the theory and to examine its accuracy and efficiency.