Approximate solution for the compression buckling of fully-anisotropic cylindrical shells

The circular cylindrical thin-walled shell is a fundamental building block of many structures, such as aircraft fuselages. When used with laminated composites, highly efficient structures may be designed. As a result, the analytical treatment of cylindrical shells has received significant attention over recent decades. However, most of the work carried out in this area concerns orthotropic laminates, i.e. those with no coupling. It is the purpose of the present analysis to develop a closed form, yet simple solution for the linear buckling of laminated circular cylindrical shell, from the Donnell's model, that includes all of the available couplings. Although, the usefulness of a linear solution for predicting buckling loads is questionable, its worth is in initial sizing and lay-up selection during the early stages of design. The resulting model could be used to examine the usefulness of different couplings that are not yet well understood. It is found that extension/shear coupling results in torsional movement of the cylinder, which when restricted, induces a secondary torsional loading on the cylinder, thus reducing its overall buckling load. When not restricted, extension/shear couplings generally give higher buckling loads.