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J. M. Rotter - One of the best experts on this subject based on the ideXlab platform.

  • IMPerfectION SENSITIVITY OF THIN ELASTIC CYLINDRICAL ShellS SUBJECT TO PARTIAL AXIAL COMPRESSION
    International Journal of Solids and Structures, 2004
    Co-Authors: Cy Y. Song, Jg Teng, J. M. Rotter
    Abstract:

    Abstract The paper addresses the buckling of an elastic cylinder under non-uniform axial compression applied at one boundary. It presents a systematic numerical investigation of the nonlinear load carrying behavior and imPerfection sensitivity of the Shell when a non-uniform axial load is applied to one end in the form of two equal-length uniformly loaded zones, diametrically opposite each other. Four imPerfection forms are examined: the linear bifurcation mode, the nonlinear buckling mode, several post-buckling deformed shapes for the Perfect Shell, and a weld depression. Additional aspects, such as the influence of the weld depression position and its wavelength are also investigated. Special attention is given to the mesh convergence study and the sign of the imPerfection amplitude. The numerical results demonstrate that the mode of the lowest linear bifurcation load is not always the `worst' imPerfection form. It is also shown that the critical position for a weld depression can be approximately located by examining the nonlinear buckling mode of the Perfect Shell and that the weld depression generally causes the lowest buckling load for this load case.

  • ImPerfection sensitivity of thin elastic cylindrical Shells subject to partial axial compression
    International Journal of Solids and Structures, 2004
    Co-Authors: Cy Y. Song, Jg Teng, J. M. Rotter
    Abstract:

    The paper addresses the buckling of an elastic cylinder under non-uniform axial compression applied at one boundary. It presents a systematic numerical investigation of the nonlinear load carrying behavior and imPerfection sensitivity of the Shell when a non-uniform axial load is applied to one end in the form of two equal-length uniformly loaded zones, diametrically opposite each other. Four imPerfection forms are examined: the linear bifurcation mode, the nonlinear buckling mode, several post-buckling deformed shapes for the Perfect Shell, and a weld depression. Additional aspects, such as the influence of the weld depression position and its wavelength are also investigated. Special attention is given to the mesh convergence study and the sign of the imPerfection amplitude. The numerical results demonstrate that the mode of the lowest linear bifurcation load is not always the 'worst' imPerfection form. It is also shown that the critical position for a weld depression can be approximately located by examining the nonlinear buckling mode of the Perfect Shell and that the weld depression generally causes the lowest buckling load for this load case.Department of Civil and Environmental Engineerin

Cy Y. Song - One of the best experts on this subject based on the ideXlab platform.

  • IMPerfectION SENSITIVITY OF THIN ELASTIC CYLINDRICAL ShellS SUBJECT TO PARTIAL AXIAL COMPRESSION
    International Journal of Solids and Structures, 2004
    Co-Authors: Cy Y. Song, Jg Teng, J. M. Rotter
    Abstract:

    Abstract The paper addresses the buckling of an elastic cylinder under non-uniform axial compression applied at one boundary. It presents a systematic numerical investigation of the nonlinear load carrying behavior and imPerfection sensitivity of the Shell when a non-uniform axial load is applied to one end in the form of two equal-length uniformly loaded zones, diametrically opposite each other. Four imPerfection forms are examined: the linear bifurcation mode, the nonlinear buckling mode, several post-buckling deformed shapes for the Perfect Shell, and a weld depression. Additional aspects, such as the influence of the weld depression position and its wavelength are also investigated. Special attention is given to the mesh convergence study and the sign of the imPerfection amplitude. The numerical results demonstrate that the mode of the lowest linear bifurcation load is not always the `worst' imPerfection form. It is also shown that the critical position for a weld depression can be approximately located by examining the nonlinear buckling mode of the Perfect Shell and that the weld depression generally causes the lowest buckling load for this load case.

  • ImPerfection sensitivity of thin elastic cylindrical Shells subject to partial axial compression
    International Journal of Solids and Structures, 2004
    Co-Authors: Cy Y. Song, Jg Teng, J. M. Rotter
    Abstract:

    The paper addresses the buckling of an elastic cylinder under non-uniform axial compression applied at one boundary. It presents a systematic numerical investigation of the nonlinear load carrying behavior and imPerfection sensitivity of the Shell when a non-uniform axial load is applied to one end in the form of two equal-length uniformly loaded zones, diametrically opposite each other. Four imPerfection forms are examined: the linear bifurcation mode, the nonlinear buckling mode, several post-buckling deformed shapes for the Perfect Shell, and a weld depression. Additional aspects, such as the influence of the weld depression position and its wavelength are also investigated. Special attention is given to the mesh convergence study and the sign of the imPerfection amplitude. The numerical results demonstrate that the mode of the lowest linear bifurcation load is not always the 'worst' imPerfection form. It is also shown that the critical position for a weld depression can be approximately located by examining the nonlinear buckling mode of the Perfect Shell and that the weld depression generally causes the lowest buckling load for this load case.Department of Civil and Environmental Engineerin

Jg Teng - One of the best experts on this subject based on the ideXlab platform.

  • IMPerfectION SENSITIVITY OF THIN ELASTIC CYLINDRICAL ShellS SUBJECT TO PARTIAL AXIAL COMPRESSION
    International Journal of Solids and Structures, 2004
    Co-Authors: Cy Y. Song, Jg Teng, J. M. Rotter
    Abstract:

    Abstract The paper addresses the buckling of an elastic cylinder under non-uniform axial compression applied at one boundary. It presents a systematic numerical investigation of the nonlinear load carrying behavior and imPerfection sensitivity of the Shell when a non-uniform axial load is applied to one end in the form of two equal-length uniformly loaded zones, diametrically opposite each other. Four imPerfection forms are examined: the linear bifurcation mode, the nonlinear buckling mode, several post-buckling deformed shapes for the Perfect Shell, and a weld depression. Additional aspects, such as the influence of the weld depression position and its wavelength are also investigated. Special attention is given to the mesh convergence study and the sign of the imPerfection amplitude. The numerical results demonstrate that the mode of the lowest linear bifurcation load is not always the `worst' imPerfection form. It is also shown that the critical position for a weld depression can be approximately located by examining the nonlinear buckling mode of the Perfect Shell and that the weld depression generally causes the lowest buckling load for this load case.

  • ImPerfection sensitivity of thin elastic cylindrical Shells subject to partial axial compression
    International Journal of Solids and Structures, 2004
    Co-Authors: Cy Y. Song, Jg Teng, J. M. Rotter
    Abstract:

    The paper addresses the buckling of an elastic cylinder under non-uniform axial compression applied at one boundary. It presents a systematic numerical investigation of the nonlinear load carrying behavior and imPerfection sensitivity of the Shell when a non-uniform axial load is applied to one end in the form of two equal-length uniformly loaded zones, diametrically opposite each other. Four imPerfection forms are examined: the linear bifurcation mode, the nonlinear buckling mode, several post-buckling deformed shapes for the Perfect Shell, and a weld depression. Additional aspects, such as the influence of the weld depression position and its wavelength are also investigated. Special attention is given to the mesh convergence study and the sign of the imPerfection amplitude. The numerical results demonstrate that the mode of the lowest linear bifurcation load is not always the 'worst' imPerfection form. It is also shown that the critical position for a weld depression can be approximately located by examining the nonlinear buckling mode of the Perfect Shell and that the weld depression generally causes the lowest buckling load for this load case.Department of Civil and Environmental Engineerin

Jan Belis - One of the best experts on this subject based on the ideXlab platform.

  • ImPerfection sensitivity of locally supported cylindrical silos subjected to uniform axial compression
    International Journal of Solids and Structures, 2016
    Co-Authors: Arne Jansseune, Wouter De Corte, Jan Belis
    Abstract:

    Abstract For the prediction of the real failure load of Shell structures, such as locally supported cylindrical steel silos under axial compression, it is convenient to take into account imPerfections. It is assumed that such silos are very sensitive to a wide range of (even small) geometric imPerfections, and that they lower the failure load significantly. Furthermore, these imPerfections caused by the fabrication or the manufacturing process, are the dominant factor in the discrepancy between the theoretical/numerical predictions based on a Perfect geometry and the experimental results of an imPerfect geometry. In other words, it is important to make a well-considered choice for an imPerfection when predicting the real failure load. However, the imPerfection sensitivity depends, among other things, on the shape of the Shell, the stiffening configuration, the boundary and loading conditions, etc. Before proceeding to the calculation of interaction curves and the development of new design rules for imPerfect barrels, it is essential to perform an extensive study to examine the influence of imPerfections to the failure behaviour and to choose a sufficiently detrimental imPerfection shape. In this study, different imPerfection forms are numerically investigated: the linear bifurcation mode, the non-linear buckling mode, several post-buckling deformed shapes of the Perfect Shell, and a weld depression type A and B. Additional aspects, such as the orientation, the amplitude of the equivalent imPerfection, and the position of the influence of the weld depression are also investigated. The present study takes into account the European normative documents and the guidelines of the recommendations of the ECCS.

  • Experimental validation of a numerical model for locally supported steel silos
    2015
    Co-Authors: Arne Jansseune, Jan Belis, Wouter De Corte
    Abstract:

    Generally, the decisive design state of locally supported axially compressed steel silos is buckling. To predict the elasto-plastic buckling load with sufficient accuracy, it is recommended to replace conservative hand calculations by computer simulations. In this way, the buckling load can be predicted based on the actual stress distribution and stress concentrations in the Shell wall taking into account the effect of imPerfections. The latter is of particular importance, since thin-walled Shells are extremely prone to small deviations relative to the Perfect Shell wall. However, to regard the numerical results as sufficiently accurate and reliable, a validated numerical model is required. In this paper, the validation of a Shell based FEM model of locally supported steel silos is done by comparing experimental to numerical results. For this, a total of seven experiments were performed on scale models. In these, two configuration types of locally supported steel silos were considered with engaged columns and partial-height U-shaped longitudinal stiffeners, respectively. Geometrically and materially non-linear Shell behaviour was used for the numerical simulations, taking into account the measurement of the initial imPerfections as measured prior to the experiments and the real stress-strain relationship. A good correspondence is shown between the experimental and numerical results, proving that the numerical model is suitable for the simulation of the failure behaviour of locally supported stiffened steel barrels.

G Gusic - One of the best experts on this subject based on the ideXlab platform.

  • Nonlinear buckling of cylinders under external pressure with nonaxisymmetric thickness imPerfections using the COMI axisymmetric Shell element
    International Journal of Solids and Structures, 2001
    Co-Authors: A Combescure, G Gusic
    Abstract:

    Abstract This paper concerns the influence of thickness imPerfections on the nonlinear buckling of cylinders under uniform external pressure. The material is assumed to behave elastically. A parametric study is performed using the COMI finite element, which allows to perform nonlinear analyses of Shells of revolution with any kind of nonaxisymmetric initial imPerfection. Let us assume that the Perfect Shell buckles with a Fourier mode m and that the initial thickness imPerfection is on Fourier mode 1, m or 2 m . As shown in a previous study on linear buckling of cylinders with thickness imPerfections, 1 and 2 m are the most harmful thickness imPerfections. We show that the nonlinear pre-buckling does not affect the buckling pressures very much. We then study the coupling with geometrical imPerfections. We show that the geometry and thickness imPerfections have a multiplicative effect on the decrease in buckling load in the nonlinear range. Finally, we show that if one uses only the measured outer radius of a Shell to input initial imPerfections, very different nonlinear buckling pressures can be obtained under the assumptions that the imPerfection is purely geometric, purely thickness, or a combination of both.