"Nonlinear Finite Element Modeling of Steel Fiber-Reinforced Composite beams under Flexural Loading"

This study presents an integrated experimental and numerical investigation of the flexural behavior of layered steel fiber–reinforced concrete (SFRC) beams. The research combines validated experimental data with nonlinear finite element (FE) modeling in ABAQUS/CAE to accurately predict structural response under four-point bending. Beam specimens with varying SFRC layer thicknesses (0–200 mm) were analyzed to evaluate the influence of fiber content, layer configuration, and fiber aspect ratio on load-bearing capacity, ductility, and energy dissipation. The concrete damage plasticity (CDP) model, combined with a nonlinear bond slip formulation and cohesive interface modeling, was employed to capture stiffness degradation, crack initiation, propagation, and post-peak softening behavior. The numerical predictions exhibited excellent agreement with experimental measurements, with peak load deviations below 3.4% and accurately reproduced displacement and ductility trends. Results demonstrate that moderate SFRC layer thicknesses (50–100 mm) achieve an optimal balance between enhanced ultimate load and improved ductility, while excessively thick SFRC layers increase stiffness but reduce post-yield deformation capacity. The study highlights the critical role of fiber bridging, bond mechanisms, and interface integrity in controlling crack development and regulating flexural performance. The findings confirm that homogenized SFRC models incorporating fiber volume fraction and aspect ratio can reliably predict structural behavior without detailed micro-modeling. Overall, the developed FE framework provides a robust and efficient tool for the design and optimization of layered SFRC beams, supporting their application in advanced structural engineering and rehabilitation practices.