Abstract: Based on the equilibrium equation of an elastic curved bar in 1 , the post-buckling behavior of a slender bar with rectangular cross-section under axial compression is studied. Let the ratio of the lengths of the sides of the cross-section be 1:26. By using Poin-care-Keller's shooting method and introducing rescaling functions, we investigate the case in which 6 is in a neighborhood of δ0= 1. The secondary bifurcations of the equilibrium state of the bar are found whenδ≠1; we also give the asymptotic unfo...