The influence of carbon and glass fiber hybridization combined with a graphene-enhanced epoxy matrix on bending fatigue response

• The bending stress and stiffness were maximized for 0.75 wt% graphene. • The hybridization should have a ratio of 0.125 with glass fibers in compression. • The glass fiber content in hybrid laminates determines the fatigue strength. • The addition of GNP leads to an increase in fatigue life. • Hybrid laminates show less sensitivity to the R-effect. The fatigue behavior of single and hybrid fiber-reinforced laminates, involving carbon and glass fibers with an epoxy matrix reinforced with graphene nanoplatelets, was studied in bending mode. From the static tests, it was observed that the bending stress and stiffness were maximized for 0.75 wt% graphene, while the most efficient hybrid laminate should have a ratio of 0.125 with the glass fiber located on the compression side and in a smaller amount. Compared to the carbon laminate with neat resin, the addition of graphene to the hybrid laminate matrix decreases the bending stress by only about 6.3%, instead of the 11.4% observed in the hybrid laminates with neat resin. However, the bending strain is about 10.5% higher than that observed for carbon laminates. The number of glass fiber layers in hybrid laminates determines the fatigue strength, an increase in which leads to shorter fatigue lives. However, the addition of GNP led to an increase in fatigue life of around 9.2% for glass fiber laminates, 10.6% for hybrid laminates, and 15.1% for carbon laminates. Finally, hybrid laminates show less sensitivity to the R-effect, but the damage increases and propagates faster at lower stress ratios due to higher stress amplitudes.