Investigation of the localised effects of multi-walled carbon nanotubes in pin-jointed composite structures

In this study, the effect of multi-walled carbon nanotubes (MWCNTs) on the bearing strength of pin-jointed glass fibre-reinforced epoxy composites was investigated. Three sets of specimens were prepared with 2 wt.% MWCNTs incorporated in different regions of the structure: unfilled (pure epoxy), partially filled (localised around the pin hole), and fully filled (entire structure). Each group was tested under tensile loading with two geometric configurations. The first group, composed entirely of pure epoxy without MWCNTs, served as the control. In the second group, only the region surrounding the pin hole (approximately one-third of the laminate) contained MWCNT-reinforced epoxy, while the remaining two-thirds were pure epoxy. The third group was fully reinforced with 2 wt.% MWCNTs throughout the matrix. Experimental results showed that the first group exhibited the lowest bearing strength. Interestingly, the second group outperformed the third group in terms of bearing capacity, suggesting that localised reinforcement around the joint region is more effective than full-area dispersion in improving joint performance.