Bending Failure Behavior of the Glass Fiber Reinforced Composite I-Beams Formed by a Novel Bending Pultrusion Processing Technique

The glass fiber reinforced resin matrix composite I-beams were designed and formed via a type of novel bending pultrusion processing technique, and the three-point bending tests were carried out to analyze the mechanical bending performances. The obtained results show that the main failure mode of the composite I-beam under the bending load is the upper structure (top flange) cracks along the length direction of the fibers, and the cracks simultaneously propagate downwards in the vertical direction. The bifurcated cracks can be found at the junction area between the top flange and web. In addition, the main bending failure mechanism of the composite I-beam includes the matrix cracking, propagation of cracks, and final fracture failure. In particular, noting that when the crack reaches the I-shaped neck position, the lateral bifurcation occurs, and the resulting secondary cracks further extend in two directions, which leads to the serious damage between the top flange and web, and the ultimate fracture failure occurs.

Automated summary

Glass fiber reinforced resin matrix composite I-beams were designed and formed using a novel bending pultrusion processing technique, and three-point bending tests were conducted to analyze their mechanical bending performances. Results show that the main failure mode involves upper structure cracks along the length of fibers under bending load, with bifurcated cracks at the top flange and web junction. The main bending failure mechanism includes matrix cracking, crack propagation, and final fracture failure, with lateral bifurcation occurring at the I-shaped neck position leading to ultimate fracture failure.