title: Dramatic increase in fatigue life in hierarchical graphene composites.
abstract: We report the synthesis and fatigue characterization of fiberglass/epoxy composites with various weight fractions of graphene platelets infiltrated into the epoxy resin as well as directly spray-coated on to the glass microfibers. Remarkably only ∼0.2% (with respect to the epoxy resin weight and ∼0.02% with respect to the entire laminate weight) of graphene additives enhanced the fatigue life of the composite in the flexural bending mode by up to 1200-fold. By contrast, under uniaxial tensile fatigue conditions, the graphene fillers resulted in ∼3-5-fold increase in fatigue life. The fatigue life increase (in the flexural bending mode) with graphene additives was ∼1-2 orders of magnitude superior to those obtained using carbon nanotubes. In situ ultrasound analysis of the nanocomposite during the cyclic fatigue test suggests that the graphene network toughens the fiberglass/epoxy-matrix interface and prevents the delamination/buckling of the glass microfibers under compressive stress. Such fatigue-resistant hierarchical materials show potential to improve the safety, reliability, and cost effectiveness of fiber-reinforced composites that are increasingly the material of choice in the aerospace, automotive, marine, sports, biomedical, and wind energy industries.
authors.forename: F
authors.initials: F
authors.lastname: Yavari
authors.forename: M A
authors.initials: MA
authors.lastname: Rafiee
authors.forename: J
authors.initials: J
authors.lastname: Rafiee
authors.forename: Z-Z
authors.initials: ZZ
authors.lastname: Yu
authors.forename: N
authors.initials: N
authors.lastname: Koratkar
mesh_terms: D004853:Epoxy Resins / Q000737:chemistry*; D006108:Graphite / Q000737:chemistry*; D013314:Stress, Mechanical
chemical_list: D004853:Epoxy Resins; D006108:Graphite