Free-Torsional Stiffness of Locally Buckled Thin-Walled Cross-Sections with Open Profiles

Abstract

The paper utilizes the approximate equivalence between local buckling and overall torsional buckling of cruciform cross section members with double axis symmetry under axial load to study the variation of the free torsional stiffness of thin-walled sections with open-profiles after buckling locally. It is found that the free-torsional stiffness is basically unchanged after the cross-section has buckled. This conclusion has significant meaning for the study of the interaction between local buckling and overall lateral-torsional buckling of thin-walled members with open profiles.