Bifurcation in Elastic-Plastic Plates
It is shown that the isotropic material behaviour assumed in the classical incremental theory has two distinct implications, one for elastic deformation and another one for plastic deformation. This inconsistency has been removed by modifying the plastic-flow rule. The modified constitutive relation is used to calculate bifurcation stress in elastic-plastic plates under uniaxial compression. The bifurcation model used in the analysis is a generalized version of Shanley’s model – here restriction is placed on the amplitude of perturbation as opposed to restriction on the increase or rate of traction imposed in conventional analysis. The bifurcation stress thus obtained is significantly lower than the corresponding stress obtained from the classical incremental theory.