Experimental and Numerical Investigations on the Effect of MWCNT-COOH and Al 2 O 3 Hybrid Nanofillers Dispersed CFRP Laminates Subjected to Projectile Impact.

Although carbon fiber-reinforced polymer (CFRP) composites have excellent intrinsic mechanical properties, they are vulnerable to impact loads because of their weak inter-laminar fracture toughness, which results in delamination damage. This study presents a novel hybrid nanofiller combination of multi-walled carbon nanotubes (MWCNT) and alumina nanoparticles (Al₂O₃) to determine improvements in the impact resistance of CFRP laminate. The projectile impact experimental study is carried out on 140 mm × 140 mm × 1.5 mm CFRP laminate with spherical and conical nose shape projectiles. The numerical study of the test plate consisting of six layers is performed, in which each layer is modeled using a shell element and connected through tiebreak contact. Using the Cowper–Symonds equation to determine the dynamic mechanical properties, the numerical validation is established considering the strain rate effect. The results, such as residual velocity, damage area, ballistic limit velocity and delamination obtained from numerical analysis, are compared with the experimental observations. In laminates with hybrid nanofillers, residual velocity decreased by 20% and 9% when spherical and conical projectiles were impacted, respectively. The study indicates that 0.1 wt% MWCNT + 1 wt% Al₂O₃ nanofiller concentration embedded CFRP offers better resistance against spherical and conical projectile impact. [ABSTRACT FROM AUTHOR]