GEOMETRIC AND MATERIAL NONLINEARITIES IN STEEL PLATES

A numerical model for the analysis of the geometric and material nonli nearities of plate and thin shell steel structures, based on the finit e element method, is presented together with its application to some p ractical examples. To account for the nonlinear behavior of steel, a g eneralized biaxial constitutive model, based on a kinematic yielding s urface, is adopted. The geometric nonlinear effects are included by co nsidering equilibrium on the deformed structure. Among the possible ap plications, a special concern is the simulation of the existing respon se beyond the conventional critical design or limiting loads in order to evaluate the actual ultimate capacity of those structures once the secondary resisting mechanisms and strength reserves of the materials are considered. The performance and reliability of the model are shown through the discussion of Some numerical examples for which reference theoretical and experimental results are available.