To the problem of buckling safety in the plastic range

The buckling behaviour of axially loaded circular cylindrical shells in the elastic-plastic region was examined: - Comments are given on the special design curves of the ECCS- and DASt-codes. - It was shown that the design formula of the various codes vary considerably. - Results of tests performed recently in Stuttgart and Karlsruhe were presented. Some of these buckling loads are located below the limit curves of the ECCS- and DASt-codes. - The collapse mode influenced by the constraint of the radial displacements at the boundary was discussed. The axisymmetric buckles in the end-zone are caused thereby. - In contrary to the compact column which fails under yielding in compression the case of the circular cylindrical shell requires a slightly higher safety factor because of unfavourable boundary conditions. - Based on the α-concept of ECCS- and DASt-codes a sufficiently safe design could be achieved by lowering the curves in the transition zone or by reducing the reduction factor α or by a combination of both. (orig.)