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Equivalent geometric imperfections for the numerical buckling strength verification of steel shell structures subject to shear
The Eurocode provides several possibilities to verify the buckling strength of cylindrical steel shells. On the one hand, it is possible to determine the load carrying capacity by means of a stress design, which is orientated towards experimental results. On the other hand, the Eurocode includes the numerical simulation of the structural behaviour as a further possibility of the buckling strength verification. The latter can be done on several modelling levels. The most sophisticated and perspective the most accurate method is a geometrically and materially nonlinear analysis with imperfections included (GMNIA). Inconsistencies exist at present between the experimentally derived buckling resistances and the results of GMNIA-calculations using the geometric imperfections prescribed in the Eurocode. These deviations are depicted by means of the basic buckling case of the cylindrical shell subject to uniform shear. In the present paper the neccessary modifications of the current regulations are discussed. Investigations are performed using the in-house finite element system FEMAS, whereas selective results are verified with the commercial FE code ABAQUS. An elasto-plastic material law with von Mises yield criterion and associated yield-rule is used for the assumed structural steel. It was demonstrated that in the whole geometrical range the imperfection amplitudes according to current regulations are too small and, therefore, the carrying capacities calculated with the GMNIA method are unsafe. The assumed independence of the geometrical parameter l/r for long cylinders can not be confirmed. The dimensionless imperfection amplitudes increase with increasing r/t and l/r. Therewith, the results quantitatively resemble those of circumferential compression.
Equivalent geometric imperfections for the numerical buckling strength verification of steel shell structures subject to shear
The Eurocode provides several possibilities to verify the buckling strength of cylindrical steel shells. On the one hand, it is possible to determine the load carrying capacity by means of a stress design, which is orientated towards experimental results. On the other hand, the Eurocode includes the numerical simulation of the structural behaviour as a further possibility of the buckling strength verification. The latter can be done on several modelling levels. The most sophisticated and perspective the most accurate method is a geometrically and materially nonlinear analysis with imperfections included (GMNIA). Inconsistencies exist at present between the experimentally derived buckling resistances and the results of GMNIA-calculations using the geometric imperfections prescribed in the Eurocode. These deviations are depicted by means of the basic buckling case of the cylindrical shell subject to uniform shear. In the present paper the neccessary modifications of the current regulations are discussed. Investigations are performed using the in-house finite element system FEMAS, whereas selective results are verified with the commercial FE code ABAQUS. An elasto-plastic material law with von Mises yield criterion and associated yield-rule is used for the assumed structural steel. It was demonstrated that in the whole geometrical range the imperfection amplitudes according to current regulations are too small and, therefore, the carrying capacities calculated with the GMNIA method are unsafe. The assumed independence of the geometrical parameter l/r for long cylinders can not be confirmed. The dimensionless imperfection amplitudes increase with increasing r/t and l/r. Therewith, the results quantitatively resemble those of circumferential compression.
Equivalent geometric imperfections for the numerical buckling strength verification of steel shell structures subject to shear
Gettel, Marco (author) / Schneider, Werner (author)
2005
8 Seiten, 8 Bilder, 15 Quellen
Conference paper
English
| British Library Conference Proceedings | 2005
| British Library Online Contents | 2006