Variance-Based Sensitivity Analysis of Stability Problems of Steel Structures using Shell Finite Elements and Nonlinear Computation Methods

摘要

The present paper deals with an analysis of the influence of initial imperfections on the ultimate limit state of slender steel members under axial compression. The theoretical analysis is based on a geometrical and material nonlinear finite element method; the steel structure is modelled using SHELL elements. The ANSYS program was applied. Sensitivity analysis is used to determine the sensitivity of strut load-carrying capacity with respect to the variance of initial imperfections. The methodology based on Sobol's variance is used for the sensitivity analysis. Input imperfections are of random origin. Majority of the input imperfections were measured and their random realizations were computed using their histograms whilst employing the LHS method. The LHS method was used in the evaluation of sensitivity indices. The computation model elaborated is unique with regard to its numerically demanding character.