Fatigue behavior of composite to aluminum single lap joints reinforced with graphene doped nylon 66 nanofibers

It is an important approach to prevent the damage mechanisms that cause sudden fractures during fatigue loading in bonding joints by modifying the matrix with nanostructured materials. The aim of this study is to examine the effect of graphene nanoplates (GNPs) doped nylon 66 (N66) nanofiber mats reinforcement on the fatigue life of composite to aluminum single lap joint. For this purpose, 1 wt%, 3 wt% and 5 wt% GNPs doped N66 nanofibers were produced by electrospinning method. The morphological characteristics, chemical bond structures and % crystallinity of these nanofiber mats was investigated by SEM, TEM, FTIR, DSC analysis. The fatigue tests of the bonding joints with single axis periodic cycle loading were performed at five different load levels as 20%, 30%, 40%, 50% and 60% of the maximum shear strength of each samples. Fatigue life of bonding joints was assessed by S-N curves plotted according to the fatigue results. Damage mechanisms of fractured surface in the bonding joints were investigated with the macro and micro images. The results show that, these composite nanofiber mats have increased the fatigue life of bonding joints in all case.