Effect of interfacial debonding on stress transfer in graphene reinforced polymer nanocomposites

A shear-lag analysis hybrid cohesive zone model is employed to investigate the stress transfer from polymer matrix to the graphene by considering the interfacial damage and debonding phenomena in graphene reinforced polymer nanocomposites. The applied stress can produce three cases for interface treatment: entirely intact, damaged and debonded. By using analytical derived relations, the distribution of axial stress in the graphene and interfacial shear stress at the three-mentioned states is determined and the applied stress to the nanocomposite which leads to damage and debonding initiation at the interface is evaluated. In addition, a sensitivity analysis is performed and the effects of graphene length, interfacial shear strength and graphene volume fraction on the axial stress of graphene, damage and debonding threshold stress along the interface and interfacial shear stress are studied. The results show that after applying a stress called second critical stress, the stress transfer between graphene and matrix at the bulk of graphene length (about 75% of the interface) stops due to debonding of this zone.