An experimental study on the effect of adding multi-walled carbon nanotubes on high-velocity impact behavior of fiber metal laminates

In this paper, the effect of adding multi-walled carbon nanotubes (MWCNTs) on high-velocity impact behavior of fiber metal laminates (FMLs) was investigated. The unreinforced and reinforced FMLs with different MWCNT weight percentages of 0.25, 0.5 and 1 were manufactured and tested under high-velocity impact loading using a gas gun and a spherical projectile. Moreover, tensile tests were performed on the unreinforced and reinforced composite laminates of FMLs. Incorporating 0.5 wt% of MWCNTs into the composite laminate of FML resulted the maximum reduction of 29.8% in projectile residual velocity and the maximum increase of 18.9% in the absorbed energy during projectile perforation compared to the unreinforced FMLs. This was consistent with the tensile test results in which maximum improvements in the strength, stiffness and toughness were obtained for the 0.5 wt% MWCNT-nanocomposite. The detailed visual inspections and SEM images showed that adding MWCNTs improved the resin-fiber adhesion consequently reduced the composite delamination and matrix cracking. Conversely, MWCNTs weakened bonding between the aluminum and composite layers and allowed the aluminum layer to experience larger plastic deformation.