Buckling of thin-walled silos and tanks under axial load - Some new aspects

The strength of thin-walled cylindrical shell structures is highly dependen t on the nature and magnitude of imperfections. Most importantly, circumfer ential imperfections have been reported to have an especially detrimental e ffect on the buckling resistance of these shells under axial load. Due to t he manufacturing techniques commonly used during the erection of steel silo s and tanks, specific types of imperfections are introduced into these stru ctures, among them circumferential weld-induced imperfections between strak es of steel plates. A study on several factors influencing the buckling of silos and tanks was carried out using the finite-element method. The intera ction between neighboring circumferential weld imperfections was investigat ed, and it was found that the influence on the buckling behavior depended o n the strake height in relation to the linear meridional bending half-wavel ength and the depth of the imperfection. The shape of localized circumferen tial weld imperfections was found to influence the buckling behavior of sil os and tanks. The influence of a recently developed shape function on the b uckling behavior has been examined. The strengthening effect of weld-induce d residual stress fields was also studied, and the extent of the increase i n buckling strength was derived for a large range of cylinder geometries.