Post-buckling behaviour of regular convex polygonal columns buckling in local and distortional modes

André Martins, Rodrigo de Moura Gonçalves, Dinar Camotim

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review


This paper presents and discusses numerical results concerning (i) the elastic local, distortional and local-distortional interactive post-buckling behaviours and (ii) the imperfection sensitivity of regular convex polygonal cross-section (RCPS) tubes under uniform compression. Although it was shown recently that the local and distortional buckling behaviours are characterised by duplicate bifurcation modes, knowledge concerning the corresponding post-buckling behaviour is still lacking. Moreover, the closeness between the local and distortional critical buckling loads invariably leads to a coupling phenomenon, i.e., local-distortional interaction, which means that sizeable post-critical strength erosion may occur, particularly if the local buckling load is the critical one. The results presented are obtained through a geometrically non-linear Generalised Beam Theory (GBT) formulation combined with a recently reported cross-section analysis specialised for RCPS members. This GBT specialisation is first employed to characterise the bifurcation behaviour, namely by helping to pinpoint the occurrence of the above three distinct buckling behaviours. Then, post-buckling results are presented and discussed for different combinations of the local-to-distortional buckling load ratio and the amplitude of the critical-mode initial geometrical imperfections, in order to assess their influence on the member imperfection sensitivity. For comparison and validation purposes, ABAQUS shell finite element values are reported.
Original languageEnglish
Title of host publicationProceedings of the 8th International Conference on Thin-Walled Structures (ICTWS 2018)
PublisherUniversidade de Lisboa
Number of pages21
Publication statusPublished - 24 Jul 2018
Event8th International Conference on Thin-Walled Structures (ICTWS 2018) - Lisbon, Portugal
Duration: 24 Jul 201827 Jul 2018
Conference number: 8th


Conference8th International Conference on Thin-Walled Structures (ICTWS 2018)
Abbreviated titleICTWS 2018


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