ON THE CORRELATION OF ANALYSES AND TESTS OF THE INELASTIC FLEXURAL BEHAVIOR OF WIDE-FLANGE STEEL BEAMS

Aspects of numerical modeling which influence the correlation between tests and finite element analyses of the inelastic stability of wide-f lange beams are discussed. Results from a series of fully non-linear s hell finite element studies are compared to data from tests used to de termine the inelastic rotation capacity of wide-flange steel beams. Th e modeling issues addressed include: (1) the distribution and magnitud e of residual stresses, (2) imperfection sensitivity, in view of possi ble yield surface comer-type effects, (3) representation of the yield plateau and strain-hardening response of structural steel, and (4) the sensitivity to variations in the yield stress. Numerical problems enc ountered in the incremental-iterative analyses and the analysis strate gies used to overcome these problems are also outlined. For the exampl es analyzed and the incremental-iterative solution approach employed, the experimental and the numerical results have been found, in general , to be in good agreement. It is shown through numerical studies that, for the particular examples considered, variations in the assumed res idual stress pattern have practically no effect on the predicted rotat ion capacity. The representation of the yield plateau and variations i n the magnitude of the initial imperfections only slightly affect the analysis results. Variations in the yield stress significantly change the model's flexural response, but they only slightly affect the predi cted rotation capacity. It is shown that small errors in measurement o f the yield stress can result in large changes of the rotation capacit y calculated from experimental data.