Recent research advances on ECBL approach.: Part I: Plastic–elastic interactive buckling of cold-formed steel sections

• Published in: Thin-walled structures Vol. 42; no. 2; pp. 177 - 194
• Main Authors: Ungureanu, V., Dubina, D.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01-02-2004
• Subjects: Elastic overall buckling; Erosion; Imperfection; Interactive plastic–elastic buckling; Local buckling; Local plastic mechanism; Thin-walled cold-formed steel members; Imperfection; Thin-walled cold-formed steel members; Elastic overall buckling; Local buckling; Local plastic mechanism; Interactive plastic–elastic buckling; Erosion
• ISSN: 0263-8231; 1879-3223
• DOI: 10.1016/S0263-8231(03)00056-9

The objective of this two parts paper is to present some recent developments and applications of
erosion of critical bifurcation load (ECBL) approach for the interactive buckling. Two different types of problems are analysed: (1)
plastic–elastic interactive buckling which implements into the Ayrton–Perry interaction formula the plastic strength of the stub columns evaluated by means of local plastic mechanism analysis, and (2)
elastic–elastic interactive buckling for members with perforations.
The first part of the paper analyses the occurrence of local plastic mechanisms in cold-formed steel sections in compression, and how they can be implemented in the ultimate limit state analysis of the members. Actually, the failure of thin-walled cold-formed members in compression always occurs with a local plastic mechanism. Starting from this observation, the authors suggest to use in the interactive local-overall buckling analysis the sectional plastic mechanism strength instead of traditional ‘effective section’. The ECBL approach is used to implement the proposed interactive buckling model. Results are compared with those of other two recent methods, namely the
direct strength method and
plastic effective width approach. Relevant tests are used to evaluate the three methods. Comparisons with European and American design codes are also presented in the paper.