| Elastic as well as plastic buckling of circular cylindrical shells filled with a core material is analyzed under axial compressive loading. A practical example of this situation is the buckling of concrete filled steel tubular (CFT) columns used widely in high-rise buildings. The theoretical problem is modeled as the bifurcation buckling of a perfect "infinitely" long circular cylindrical shell under uniform compression, constrained by a one-way (tension-less) foundation. An important and useful novelty is that the shell material is allowed to undergo strain-hardening plasticity before buckling. For simplicity, the core material is assumed to remain elastic. The approach is analytical. The governing equations are solved exactly to obtain buckling loads, and wavelengths in contact and no-contact regions. The theoretical results, when applied to CFT columns, are found to be in very good agreement with the experimental buckling loads of other researchers. |
