On the mechanics of local-distortional interaction in thin-walled lipped channel beams

André Dias Martins, Dinar Camotim, Rodrigo Gonçalves, Pedro Borges Dinis

Research output: Contribution to journalConference articlepeer-review

22 Citations (Scopus)


This paper investigates the elastic post-buckling behaviour of simply supported thin-walled lipped channel beams undergoing local-distortional (L-D) interaction. The beams are uniformly bent about the major-axis and experience flange-triggered local buckling (most common situation in practice). Three beam geometries are considered, each exhibiting a different type of L-D interaction, namely (i) “true L-D interaction“ (close local and distortional critical buckling moments - two critical-mode initial geometrical imperfections are used, akin to the competing critical buckling modes), (ii) “secondary local-bifurcation L-D interaction“ or (iii) “secondary distortional-bifurcation L-D interaction“ (critical distortional-to-local buckling moment ratio well below or above 1.0, respectively, with “high enough“ yield stresses). The results presented and discussed are obtained through elastic geometrically non-linear Generalised Beam Theory (GBT) analyses and provide the evolution, along given equilibrium paths, of the beam deformed configuration (expressed in GBT modal form), relevant displacement profiles and modal participation diagrams, making it possible to acquire in-depth knowledge on the beam L-D interaction mechanics. Particular attention is devoted to interpreting the quantitative and qualitative differences exhibited by the beam post-buckling behaviours associated with the three aforementioned L-D interaction types.

Original languageEnglish
Pages (from-to)108-125
JournalThin-Walled Structures
Issue numberSI
Publication statusPublished - 1 Jul 2018
Event7th International Conference on Coupled Instabilities in Metal Structures (CIMS) - Baltimore, United States
Duration: 7 Nov 20168 Nov 2016


  • Generalised Beam Theory (GBT)
  • Geometrically non-linear analysis
  • Local-distortional interaction
  • Thin-walled lipped channel beams
  • True and secondary-bifurcation L-D interaction


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