Investigation on Flexural Properties of Intra-layer Hybrid Composite Laminates Reinforced with Carbon and Glass Fibers

In this work, the effects of intra-layer hybridization on the flexural properties and failure mechanisms of composite laminates were experimentally and numerically investigated. Test specimens were prepared via the thermo-forming technique with plain woven fabrics reinforced using net carbon, glass, and their intra-layer hybrids. The force–displacement curves, failure modes, and flexural properties were analyzed and compared. The experimental results revealed that the catastrophic failure modes of carbon fiber-reinforced composite laminates can be improved after hybridization with glass fibers. However, the flexural properties of the composite laminates, such as flexural strength and modulus, depended on the type of fiber along the longitudinal (i.e., load-carrying) direction. A higher flexural strain can be obtained by replacing the longitudinal carbon fiber yarns with glass fiber ones. Subsequently, finite element models that considered the inter-layer and intra-layer deformation behaviors were established and validated with the tested results. The maximum error between the experimental and predicted flexural properties was 6.15%. The fracture process and stress distribution of the specimens were predicted and analyzed to understand the failure mechanisms. Notably, it was observed that intra-layer hybridization critically affected the transverse stress distribution state across the thickness of the composites, which resulted in complicated failure behaviors among adjacent fiber yarns. Finally, the effects of interfacial properties on the flexural responses were simulated and analyzed.