Buckling of thin cylindrical shells under uniform axial compression

The classical buckling theory, linear and nonlinear finite element methods are employed to analyze the buckling of thin cylindrical shells under uniform axial compression. The initial buckling loads predicated by the three methods are approximately the same. Nonlinear finite element study reveals that there is a nearly－ horizontal length in the post－ buckling load- deflection space, corresponding to the nearly－ constant post－ buckling load. An empirical formula to predict the buckling stress is drawn from statistics on experimental data, comparisons between the results from the formula and the ones from nonlinear finite element study lead to the conclusion that the experimental buckling stress is actually the theoretical post－ buckling stress, rather than the initial buckling stress. This is a reasonable explanation to the disturbing fact that the experimental buckling loads were often much below the predications of classical theory.