Strain energy release rate and mode-I delamination growth in carbon-graphene/epoxy hybrid nanocomposites

The influence of graphene reinforcement in strain energy release rate (G(IC)) and Mode-I delamination growth in carbongraphene/epoxy (CG-Ep) hybrid nanocomposites have been studied using the double cantilever beam (DCB) test. The specimens of carbon/epoxy (C-Ep) and CG-Ep nanocomposites were manufactured using vacuum assisted manual lay-up method. DCB tests were conducted in a displacement controlled mode to achieve stable delamination growth under static loading. At the onset of delamination growth, the load ((Pcr)) and the total opening displacement (delta(cr)) were recorded. The total compliance of the DCB specimen was obtained using, C = delta/P. P-cr and delta(cr) are recorded as a function of the delamination length (a). Plots of critical loads and compliances as a function of the delamination size were used in computing G(IC), the Mode-I critical strain energy release rate. The delaminated zone was studied through fractographic examinations and surface roughness measurement. The results show improved G(IC) of CG-Ep nanocomposites in comparison to traditional C-Ep composites. The fractured surface of CG-Ep shows undulated surface with increased roughness which possibly contributed in crack deflection mechanisms. (C) 2015 The Authors. Published by Elsevier Ltd.