Effect of graphene and mwcnts on mode ⅰ interlaminar fracture toughness of CFRP

Unidirectional carbon fiber-reinforced composites are widely applied in aeronautical and astronautical structures. However, the weak interlaminar toughness makes composite structures easily being damaged under the low energy impact. Improving composite interlaminar toughness becomes possible as the carbon nanotubes and graphene were discovered. This paper focuses on enhancing the mode I fracture toughness by adding two nano materials of multi-walled carbon nanotubes(MWCNTs) and multi-layers graphene(mG) into interlaminar surface. MWCNTs and mG are sprayed on the central two plies interlaminar surface at the same density 1g/m². Double cantilever beam(DCB) standard test is used to investigate the mode I energy release rate with different toughening strategies. Increasing proportion of the mean fracture toughness are 20.3% (MWCNTs) and 103.2% (mG) respectively. According to SEM analysis, it is revealed that the multi-layers graphene relatively larger superficial area makes the interlaminar fracture toughness increasing remarkably.