Abstract
This paper deals with the ultimate strength of unstiffened and longitudinally stiffened plates subjected to biaxial in-plane forces. Firstly, the elastic buckling strength and corresponding buckling modes of stiffened plates are investigated in order to deduced the required minimum relative stiffness of a stiffener, and to decide the initial deflection modes of analytical models for analyzing the ultimate strength of stiffened plates parametrically. Then, the ultimate strength of unstiffened and stiffened plates are investigated through the elasto-plastic and finite displacement analyses on the basis of a finite element method. Finally, a simple and approximate interaction curve for the ultimate strength of unstiffened and stiffened plates is proposed.
