Buckling of thin cylindrical shells under axial compression

Simple experiments on self-weight buckling of thin, open-top, ®xed-base, small-scale silicone rubber cylindrical shells are presented in this article. The buckling heights were found to be proportional to thickness raised to the power of approximately 1.5, compared to 1.0 as in the classical theory. A non-linear ®nite-element analysis of self- weight buckling showed that there is a `post-buckling plateauʹ load corresponding to the experimental buckling loads. Moreover, the results of the present experiments showed very little `scatterʹ in the buckling heights, compared to the large scatter in the experimental data from the literature on the buckling of thin cylindrical shells under axial compressive load (which also have buckling stress proportional to thickness raised to the power of approximately 1.5), although there were measurable imperfections in terms of thickness variations. These observations somehow defy the accepted hypothesis of `imperfection-sensitivityʹ in shell buckling. The most obvious explanation of the di€erence is that the open-topped shells of the present study are statically determinate, whereas the usual closed- ended shells of tests reported in the literature are statically indeterminate; the possibility of high initial stresses may explain the scatter in the experimental observations in the literature.