A special beam element for the analysis of thin‐walled structural components

A new beam element is described which is capable of depicting the non-linear elastic mode interaction of overall bending/buckling with local buckling in thin-walled beam-columns. In addition to being capable of describing overall biaxial bending and twisting, the element has shape functions which contain implictly the relevant local buckling deformation. The mode interaction occurs by virtue of the non-linear coupling of the overall and local buckling deformation. The local and post-local buckling displacement fields are computed a priori in an efficient manner using the finite strip technique. The modulation of the local buckling amplitudes is also accounted for in the element. In general, the beam element incorporates three companion local modes, all of which may become important in the process of interaction. Examples are presented which illustrate the efficacy of the element for problems involving interaction of local and flexural buckling modes and the combined interaction of local, flexural and flexural--torsional modes.