On the dispersion and experimental investigation on transverse tensile low-cycle-fatigue behaviour of GFRP nanocomposites filled with CNTs and GNPs

[Display omitted] •Fiber volume fraction of laminates controls the reinforcement efficiency of nanoparticles in 3-phased nanocomposites.•Similar SSA and density promotes functional synergism between the co-carbon nanoparticles.•Under 3-point bend test laminates sustain load till there is fracture in mid-plane or neutral axis.•Damage in mid-plane promotes failure in tensile region at a rapid pace. Improvements in the thermo-mechanical properties of nanocomposites (NCs), particularly containing nanoparticles (NPs) in the resin largely depends upon the dispersion state of nanoparticles in the matrix phase. A 3-phased GF-NC-Epoxy composite prepared by such method witnesses a final reduction in the volume fraction of nanoparticles due to overall reduction in the matrix volume fraction. This work explores an effective dispersion method based on rheological behaviour of 2-phased NCs and compares the efficacy of the same in dispersion of 0.5 wt% carbon nanotubes (CNTs), graphene nanoplatelets (GNPs) and their mixture in the ratio of 1:1 (GPNTs). The NPs possess close densities and specific surface area (SSA) of SSACNT = 330 m2/g; SSAGNP = 300 m2/g; ρCNT=0.28g/cm3;andρGNP=0.3g/cm3. The prepared GFRP laminates were tested for their static and dynamic (low cycle fatigue (LCF)) flexure properties and it was observed that the effectiveness of nanoparticles depends upon their final volume fraction in the laminates. A laminate containing higher fiber volume fraction (vf) witnessed large improvement in the static strength post addition of NPs due to improved toughness, but they often witness early failure under fatigue loading owing to limited toughening due to lesser volume of NPs in the matrix phase. It was also observed that once the samples witnessed a crack in the midplane, it requires only few cycling to fail abruptly.