Buckling behaviour of extensively-welded steel cylinders under axial compression

Abstract

Thin cylindrical shells in large steel silos and tanks are generally constructed from a large number of rolled panels with many circumferential and meridional welds. This extensive use of welding is expected to lead to unique imperfections and residual stresses that can greatly reduce the buckling strength of these shells when subject to axial compression. While many studies have examined the buckling strength of cylindrical shells with one or more circumferential welds, no previous study has considered the buckling strength of cylindrical shells with multiple circumferential welds together with a large number of short meridional welds as found in large civil engineering steel shells. This chapter presents the results of the first two tests on laboratory models of such extensively welded shells. The experimental procedure is described first. Typical test results are summarized and compared with finite element predictions, which do not account for the effect of welding-induced residual stresses. These comparisons indicate that the effect of residual stresses in these shells may be considerable, and may be either detrimental or beneficial. This chapter has been concerned with the buckling behavior of laboratory models of large steel cylindrical shells featuring many welds, as found in large civil engineering shell structures such as steel silos and tanks. The chapter introduces an innovative method for the fabrication of laboratory models, together with the test set-up. The fabrication method successfully produced models with an oscillating pattern of imperfections and these imperfections had a severe effect on the buckling strengths as revealed by the buckling tests and nonlinear finite element analyses (FEA).