# Validation of AISI Design of Cold-Formed Steel Beams Using Non-Linear Finite Element Analysis  
[PERSON]  
1 Department of Civil Engineering, The University of Lahore, Lahore 54590, Pakistan; [EMAIL_ADDRESS] (2)[EMAIL_ADDRESS] (Z.A.S. )1  
[PERSON]  
1 Department of Civil Engineering, The University of Lahore, Lahore 54590, Pakistan; [EMAIL_ADDRESS] (2)[EMAIL_ADDRESS] (Z.A.S. )1  
[PERSON]  
1 Department of Civil Engineering, The University of Lahore, Lahore 54590, Pakistan; [EMAIL_ADDRESS] (2)[EMAIL_ADDRESS] (Z.A.S. )1  
[PERSON]  
2 School of Construction Management & Quantity Surveying, College of Engineering, Construction and Living Sciences, Otago Polytechnic, Duneta 9016, New Zealand2  
Footnote 12: [[https://www.md](https://www.md)]([https://www.md](https://www.md))characteristics of CFS cross-sections. It enables the elastic analysis of local, distortional, and global buckling modes and provides basic data for the application of DSM in design. While the CUFSM and DSM provide a robust framework for predicting the behavior of CFS members, it is critical to validate these analytical approaches against more comprehensive and detailed methods. Non-linear finite element analysis (FEA) using software such as ABAQUS offers a high-fidelity approach to modeling the complex behavior of CFS sections under various loading conditions. By incorporating material and geometric non-linearities, FEA can capture the actual behavior of CFS members more accurately than linear analytical methods. Thus, validating CUFSM and DSM predictions using results obtained from non-linear FEA can increase confidence in these methods and ensure their reliability in practical design applications. Cold-formed steel elements are thin, light, and cost-effective. However, this efficiency comes with complications. Engineers must account for cross-sectional instability (i.e., local and distortional), in addition to the global buckling of the member [1]. The Direct Strength Method does not use effective width or iteration to determine the strength of the element for design. Instead, the designer must calculate the elastic buckling load for three cases of behavior: local, distortional, and global. These data, combined with the load that causes the first yield, are then analyzed and used to \"directly\" provide strength using simple prediction equations [2]. In another study, the analysis was carried out using the four-point bending method. For a thin-walled beam with an open cross-section, where the load and support act at the shear center, it is not possible to eliminate the torsional moment load because the investigated beams are not perfect [3]. CUFSM is a useful tool for identifying buckling classes, i.e., global, distortional, local, and other deformations, and the constrained finite strip method can provide both modal decomposition and modal identification of the conventional finite strip solution [4]. [PERSON] and [PERSON] created a cross-sectional model in CUFSM and an eigenvalue analysis was then performed to determine the expected imperfection modes. The CUFSM model was then exported to ABAQUS (via an input file) to run an eigenvalue buckling analysis using the same imperfection modes [5]. In developing the DSM, [PERSON] and [PERSON] performed two series of bending tests and finite element analyses on different C- and Z-profiles including local buckling [6] and deformational buckling [7]. These series were aimed at isolating the local and biased modes used in DSM validation [8]. Artificial Intelligence techniques were also applied for the prediction of the axial capacity of cold-formed steel channel sections to compare the results with those of EWM and DSM, leading to proposed improvements in the AS/NZS 4600:2018 design equations [9; 10; 11]. The increasing use of back-to-back built-up cold-formed steel (CFS) channel beams, valued for their cost-effectiveness and higher load capacities, is evaluated. This evaluation involves 12 experimental tests and a non-linear finite element (FE) model.