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چکیده
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The structural analysis of cold-formed steel (CFS) members with geometric discontinuities, such as web openings, presents significant challenges due to the local effects they introduce and the limitations of traditional mesh-based methods. In this study, a hybrid numerical approach is proposed, combining the Improved Element-Free Galerkin (IEFG) method with the classical Finite Strip (FS) method to investigate the buckling behavior of CFS channel-section beams with web holes under bending loads. The structure is partitioned into two sub-domains: regions containing openings are modeled using the IEFG method, which offers high accuracy in handling irregular geometries and stress concentrations, while the remaining domain is analyzed using the FS method for its efficiency in modeling prismatic members. The coupling between the two methods is achieved through Lagrange multipliers to ensure continuity of displacement and boundary conditions across the interface. Numerical results indicate that the proposed IEFG-FS method not only maintains high accuracy but also significantly reduces computational effort up to 50% in some cases compared to conventional approaches. The study further demonstrates that the presence of web openings leads to a notable reduction in the critical moment for buckling, especially in local buckling modes. This reduction ranges approximately from 9% to 33% for local buckling, and to a lesser extent for distortional and global modes. Additionally, it is found that transverse coupling of FS strips to the meshfree domain improves the accuracy of results compared to longitudinal coupling. Overall, the IEFG-FS approach offers a robust and efficient framework for the buckling analysis of perforated CFS members, making it a valuable tool for structural engineers dealing with complex geometries and local instabilities.
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