Effects of initial imperfections on nonlinear behaviors of thin-walled members

The effects of the initial imperfections on the nonlinear behaviors and ultimate strength ofthe thin-walled members subjected to the axial loads, obtained by the finite element stability analysis, areexamined. As the initial imperfections, the buckling mode shapes of the members are adopted. Thebuckling mode shapes of the thin-walled members are obtained by the transfer matrix method. In thefinite element stability analysis, isoparametric degenerated shell element is used, and the geometrical andmaterial nonlinearity are considered based on the Green Lagrange strain definition and the Prandtl-Reussstress-strain relation following the von Mises yield criterion. The U-, box- and I-section memberssubjected to the axial loads are adopted for numerical examples, and the effects of the initialimperfections on the nonlinear behaviors and ultimate strength of the members are examined.