Effects of the graphene nanoplatelets reinforced interphase on mechanical properties of carbon fibre reinforced polymer – A multiscale modelling study

Abstract

Mechanical properties of carbon fibre reinforced polymer (CFRP) are greatly affected by an interphase between fibre and matrix. Coating fibre with nanofillers has been suggested to improve the interphase properties. In this paper, a multiscale modelling framework was developed to investigate how graphene nanoplatelets (GnPs) influence the mechanical properties of CFRP laminate by reinforcing the interphase. At the nanoscale, the Mori-Tanaka homogenisation method was used to determine effective properties of the GnPs reinforced interphase. GnPs reinforced interphase properties at different GnPs orientations, and volume fractions were examined. At the microscale, a 3-D representative volume element (RVE) model based on obtained interphase properties was used to predict the elastic constants of CFRP unidirectional lamina. This RVE model consisted of three phases: carbon fibre, epoxy resin and the GnPs reinforced interphase. The incorporation of GnPs in the interphase increased both longitudinal and transverse lamina moduli. Finally, simulations of the three-point bending test were performed on the macroscale CFRP laminate. The macroscale modelling based on predicted lamina properties was found to reproduce experimentally measured flexural modulus well. It was found that the GnPs coating on fibre has a positive influence on the mechanical properties of CFRP, and the enhancement varied with orientation and local volume fraction of GnPs. In the presence of GnPs coating, 0° and 90° flexural moduli of CFRP laminate increased by 6.1% and 28.3% respectively.