The failure of thin-walled lipped channel compression members due to coupled local-distortional interactions and material yielding

This paper details appropriate finite element modelling strategies and procedures for the determination of the coupled local-distortional interactive response of thin-walled lipped channel sections. The modelling procedures are able to describe the complete loading history of the compression members from the onset of local buckling through post-local buckling behaviour leading to local-distortional interaction including material yielding and yield propagation to ultimate conditions and then to elasto-plastic unloading. The numerical simulations take due account of the influence of geometrical imperfections on the compressive ultimate failures of the sections and the results from the finite element models are shown to agree favourably with the ultimate loads and failure mechanisms from experimental tests on steel lipped channel sections exhibiting local-distortional interaction.