POSTBUCKLING OF ONE-DIMENSIONAL ELEMENTS WITH THIN-WALLED ANGLE SECTION USING SIMPLIFIED MODELS

The present work is a detailed study of the initial post-critical beha vior of one-dimensional elements with an angle section, using simplifi ed models. The emphasis of the work is on the influence that the defor mation of the cross section has on the critical and post-critical stat es. The model assumes that the cross section deforms entirely by rotat ion of the legs about the hinge at the apex. Three structural types ar e considered: the column under an axial load, the circular arch under a central load, and the circular ring under uniform radial pressure. C ritical states are assumed to be distinct, in the sense that mode inte raction effects may be neglected. The critical states for all cases an alyzed are unaffected by angle deformation, while the post-critical st ates are affected to different degrees, depending on the structural co nfigurations. A parameter that defines post-critical strength has been consistently defined for the cases of the column and the arch. The un stable post-critical behavior found for short angle columns makes this type of structure sensitive to imperfections.