Structural performance of laminated composite thin-walled beams under four-point bending

This study focuses on evaluating flexural behavior of carbon fiber-reinforced polymer laminated composite thin-walled I-beams. In order to verify the effectiveness, a total of seven specimens were analyzed in this study with constant flange width 100 mm and web height 200 mm. The I-beam implemented plywood as the core of the web and flanges with 10 mm thickness in flanges and 5 mm thickness in web with total length of 1350 mm and support span with 1200 mm. The beams were analyzed under four-point bending, and the flexural behavior of these beams has been evaluated analytically based on theoretical fundamentals. Additionally, a finite element model has been developed using ANSYS software program to validate the results, and it has been seen a very good agreement between results. Two influential parameters were considered including: (i) the effect of changing the stacking sequence and ply orientation, (ii) the effect of changing the shear span-to-depth ratio. Results indicated that in cases where decreasing number of flange laminates, the bending stiffness of composite beams was notably reduced. However, this negative effect could be avoided by increasing the number of flange laminates with 0°, and reducing the shear span-to-depth ratios of the beams led to the change of the damage mechanisms from delamination to compression buckling of top flange.