Summary The general theory of bifurcation and uniqueness for elasticplastic solids and the asymptotic theory of initial postbifurcation behavior in the plastic range are briefly reviewed. A column with an asymmetric cross-section is used to illustrate some of the interactions between geometrical and material nonlinearities that occur in plastic buckling problems. Then, for the cruciform column, the influence of a corner theory of plasticity on postbifurcation behavior and imperfection sensitivity is analyzed in detail. An asymptotic analysis of imperfection sensitivity in the plastic range, which neglects elastic unloading, is presented. Some of the results obtained by this theory are discussed and compared with results of full numerical solutions accounting for the actual elasticplastic material behavior. Finally, the localization of initially periodic buckling patterns is considered, and numerical computations of the actual localization process are presented for several elasticplastic structures.
