Design of Thin-Walled Steel Structures Susceptible to Interactive Buckling

This final year’s project investigates the interactive buckling behavior of thin-walled rectangular steel section columns subjected to axial compression through a point load. These structural members can be efficient and lightweight but can also be highly sensitive during the interaction of local ang global buckling phenomena. This interaction might result in instability which leads to premature failure and imperfection sensitivity, posing challenges to the current design approaches. Finite element analysis (FEA) has been used by ABAQUS software to precisely simulate the realistic effects of the boundary conditions, material nonlinearity, geometric imperfections and residual stresses. Particular attention was given to the presence of residual stress due to the welding process, since they have shown a significant reduction in structural capacity. The validation process involved comparison against experimental data from Yang et al. (2017) and numerical studies by Shen & Wadee (2019a), demonstrating good agreement in failure modes and ultimate load predictions. Proceeding with an automated GMNIA (Geometrically and Materially Nonlinear Imperfect Analysis) using a Python script, this project conducted extensive parametric studies efficiently. The extracted data was then compared with Eurocode 3 (EC3) design curves, showing conservative and non-conservative discrepancies. To address the present limitations of the Effective Width Method (EWM), a new normalization approach was adopted. The findings demonstrate the need for an improvement of design guidance and the importance of including both interaction effects and residual stresses during the stability assessment.