Buckling analysis of thin-walled sections under localised loading using the semi-analytical finite strip method

• The Semi-Analytical Finite Strip Method (SAFSM) is used for the analyses.
• Localised loading as occurs in web crippling is investigated.
• Simple plates and channel sections under localised loading with both plain and longitudinally stiffened webs are studied.
• Solutions are checked against classical solutions, the Spline Finite Strip Method (SFSM) and the Finite Element Method (FEM).

Thin-walled sections under localised loading may lead to web crippling of the sections. This paper develops the Semi-Analytical Finite Strip Method (SAFSM) for thin-walled sections subject to localised loading to investigate web crippling phenomena. The method is benchmarked against analytical solutions, Finite Element Method (FEM) solutions, as well as Spline Finite Strip Method (SFSM) solutions. The paper summarises the SAFSM theory then applies it to the buckling of plates, and channel sections under localised loading. Multiple series terms in the longitudinal direction are used to compute the pre-buckling stresses in the plates and sections, and to perform the buckling analyses using these stresses. Solution convergence with increasing numbers of series terms is provided in the paper. The more localised the loading and buckling mode, the more series terms are required for accurate solutions. The loading cases of Interior One Flange (IOF) and Interior Two Flange (ITF) are investigated in this paper using simply supported boundary conditions.