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

The effects of the initial imperfections on the nonlinear behaviors and ult imate strength of the thin-walled members subjected to the axial loads, obt ained by the finite element stability analysis, are examined. As the initia l imperfections, the buckling mode shapes of the members are adopted. The b uckling mode shapes of the thin-walled members are obtained by the transfer matrix method. In the finite element stability analysis, isoparametric deg enerated shell element is used, and the geometrical and material nonlineari ty are considered based on the Green Lagrange strain definition and the Pra ndtl-Reuss stress-strain relation following the von Mises yield criterion. The U-, box- and I-section members subjected to the axial loads are adopted for numerical examples, and the effects of the initial imperfections on th e nonlinear behaviors and ultimate strength of the members are examined.