Investigations on low-velocity ballistic impact behaviour of Kevlar / Epoxy composites reinforced with chopped wet spun fibers intruded with nanofillers

The low-velocity ballistic behaviour of chopped fiber-reinforced Kevlar Epoxy composites has been investigated. The chopped fibers of ‘Poly Vinyl Alcohol’ were fabricated using a wet spinning machine and intruded with functionalised Carbon Nanotubes and reduced Graphene Oxide (rGO) both individually and synergistically. The characterisation performed on the spun fibers indicated that the addition of fillers improved the properties owing to the increase in the surface interactions. The tensile strength was seen to increase with the addition of fillers and a maximum improvement of 214.74 % was observed for the fiber with both CNT and rGO filler addition. These fibers were chopped and incorporated into the composites prepared by the ‘hand layup’ process. Tensile and Inter Laminar Shear Strength tests conducted on the prepared composite samples revealed that the hybrid samples had the maximum values. The chopped fiber with both the filler addition had an improvement of 15.02 % in tensile strength, 17.45 % in modulus and 67 % in Inter Laminar Shear Stress (ILSS). This combination had the highest resistance to the projectile's motion under low-velocity ballistic impact also. All the targets were able to ‘ricochet’ the projectile with large Depth of Penetration values. The lowest DoP, lowest strike face cracking and no delamination was observed for the optimum reinforced composite target. The presence of chopped fiber improves the toughness by crack bridging, load sharing and creating prestressing in the composite.