Basic Theory and Numerical Example for Elasto-Plastic and Finite Displancement Analysis of Stiffened Plates with Opening Subjected to Compression

Described in this paper is a basic theory for elasto-plastic and finite displacement analysis of stif­ .fened plates with the opening subjected to compression in consideration of the initial imperfections such as initial deflection and residual stress on the basis of a finite element method. In this theory, the geometrical nonlinearity caused by the large deflection of plates is formulated according to a total Lagrangian method of removing the rigid body displacement from the global deformation of a finite element, and then the yield condition of von Mises and the plastic flow rule of Prandtl-Reuss with strain hardening are used to simulate elasto-plastic nonlinear behavior of steel material. Unbalanced forces between true nodal forces and applied nodal forces in each step of the iteration calculation are eliminated by the Newton-Raphson's method. A short box column consisting of two mild steel stif­ fened plates with a circular hole in each of them and two high strength steel flange plates are analy­ zed as a numerical example. Moreover, these numerical results are compared with the experimental results corresponding to the short box column.