On the behavior of multiscale carbon fiber-epoxy composites containing graphene nanoplatelets under transverse loading

Composite materials due to their unique properties such as high specific strength and stiffness have gained many applications in automotive, aerospace, transportation and other industries. In this study, the effects of addinggraphene nanoplatelets (GNPs)in various weight percentages (0, 0.1, 0.2, 0.3, 0.4 and 0.5 with respect to matrix) on the flexuralbehaviorof carbon-fiber reinforced epoxy compositeswereassessed. For dispersion of GNPs into the polymer matrix, high speed mechanical stirrer andultrasonic waves were used. Hand lay-up method was used for fabricating the composites, and three-point bendtest for assessing their flexural behavior.Results demonstrated that the maximum improvement in flexural properties was obtained with the optimal amount of 0.4 wt.% of GNPs.The percent enhancements in flexural strength, flexural modulus,and energy absorptionwere 39, 135,and 47, respectively. Also, electron microscopy studies revealed that the addition ofGNPs had a great influence in improving the interfacial characteristics between the matrix and the carbon fibers.