Abstract: A non linear interval iteration method is applied to trace the post buckling equilibrium path of structures. Two equilibrium configurations of pre buckling and post buckling near critical loads have been obtained automatically, which avoids stopping of iteration resulting from singularity of stiffness matrixes. Some typical numerical examples show that the method can go through limit points and trace the equilibrium path of post buckling. While dealing with the so called snap back problems, the method is especially effective.

Key words: inter val iter atio n method, post -buckling, no n-linearity