Experimental and numerical analysis on mode II fracture toughness of CFRP adhesive joints using a nonlinear cohesive/friction coupled model

In this work, a nonlinear cohesive/friction coupled model was proposed by combining experiments and nu-merical simulations for mode II fracture analysis of hybrid carbon nanofillers toughened carbon fiber composite bonded joints. First, end-notched flexure tests were performed to investigate the toughening effects of multi-walled carbon nanotubes (MWCNTs) and graphene nanoplates (GNPs) hybrids modified adhesive on mode II fracture toughness of adhesive joints. Testing results show that 0.75 wt% MWCNTs/GNPs hybrid has an improvement of 45% compared to pure adhesive. Secondly, a phenomenological progressive rising friction model was introduced into an exponential cohesive zone model for delamination analysis of adhesive layer under shear and normal compression loadings. Finally, the proposed model was implemented in ABAQUS/Explicit via user subroutine VUMAT and model parameters were determined by fitting experimental results of end-notched flexure tests for adhesive joints.

Automated summary

In this study, a nonlinear cohesive/friction coupled model was proposed to analyze the mode II fracture of carbon fiber composite bonded joints with hybrid carbon nanofillers. Experimental results showed that the adhesive modified with 0.75 wt% MWCNTs/GNPs hybrid improved the fracture toughness by 45% compared to pure adhesive. The proposed model combined a phenomenological progressive rising friction model and an exponential cohesive zone model for the analysis of delamination in the adhesive layer.