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The shell buckling capacity curve 

The shell buckling capacity curve 

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Article
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p. 2535-2546 Steel silos are often supported on a small number of columns to facilitate emptying operations. The connection between these columns and an elevated cylindrical metal silo shell is a long-standing difficult problem in shell analysis. The presence of local supports beneath a cylinder leads to stress concentrations in the cylindrical wal...

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Context 1
... columns subjected to compression, plasticity and instability are the two main failure phenomena. Both effects and their interaction are described by means of buckling curves. For shell structures, similar curves are needed. In these capacity curves (Fig. 6) the buckling strength relative to the material failure condition χ is plotted as a function of the relative slenderness λ. The effect of imperfections and the interaction between ...
Context 2
... λ 0 can all be simply and accurately extracted using Fig. 7, whilst the interaction exponent η is easily found thereafter by a best fitting procedure. In EN 1993-1-6 [5], due to a lack of detailed relevant data, η is assumed to take the value η=1.0, corresponding to a straight line for elastic-plastic buckling in the traditional capacity curve (Fig. ...

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p. 2569-2576 The main part of a traditional silo is the cylindrical shell placed upon a limited number of support columns in order to facilitate emptying operations. These local supports lead to stress concentrations in the cylinder and can cause local instabilities of the shell. In order to prevent this failure phenomenon, the cylindrical shell ca...

Citations

... Other researchers are continuing to investigate this topic on a highly sophisticated numerical level, e.g. Vanlaere et al. [7], Doerich et al. [2], in order to gain a more clear insight in the buckling phenomena, to predict elastic-plastic stability behaviour and to match their experimental results. ...
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Frequently, steel silos are supported by discrete supports or columns to permit easy access beneath the barrel. In such cases, large loads are transferred to the limited number of supports, causing locally high axial compressive stress concentrations in the shell wall above the supports. If not dealt with properly, these increased stresses will lead to premature failure of the silo due to local instability in the regions above the supports. Local stiffening near the supports is a way to improve the buckling resistance, as material is added in the region of elevated stresses, levelling these out to values found in uniformly supported silos. The aim of a study on the properties of local stiffening will then be to increase the failure load, governed by an interaction of plastic collapse and elastic instability, to that of a discrete supported silo. However, during the course of such a study it was found that, although the failure remains local, the cylinder height is also a parameter that influences the failure mechanism, a fact that is not properly taken into account in current design practice and codes. This paper describes the mechanism behind the effect of the cylinder height on the failure load, which is related to pre-buckling deformations of the shell structure. All results and conclusions are based on geometrically and materially non-linear finite element analyses.