Analysis of plastic buckling of steel plates
Plasticity in steel is characterized by an appreciable amount of plastic flow (in the yield plateau range) which precedes strain hardening. This study is devoted to an analytical evaluation of the effective plastic shear modulus of fully yielded steel plates at the instant of buckling. It is assumed that yielding of steel follows the Tresca yield criterion and that plastic deformation of a steel plate is caused by slips. The Tresca yield criterion provides lower bending stiffness than that obtained from the von Mises yield criterion, but it does not lower the plastic shear modulus of the material at any point on the yield plateau. A new theory is proposed here that assumes a nonuniform distribution of slips depending on the orientation of an infinite number of possible slip planes at each point in the plate. The twisting of the plate is then accompanied by distorsion of its sectional shape, and this mode of buckling is shown to provide a considerable reduction in the effective plastic shear modulus. Applying this sectional stiffness and solving the differential equilibrium equation lead to a lower bifurcation strength, which provides much better correlations with experimental results than previous predictions.
scientific article; zbMATH DE number 168873