Manufacturing shear-thickening-gel applied carbon fibre-reinforced polymer (SACFRP) with high toughness and enhanced impact-resistant performance

Abstract

The brittle nature of carbon fibre-reinforced polymer (CFRP) causes it to be vulnerable to out-of-plane low-velocity impact (LVI). This work developed a novel manufacturing method for shear-thickening-gel applied carbon fibre-reinforced polymer (SACFRP) to mitigate brittleness and improve impact performance. The unidirectional (UD) carbon fibre fabrics were treated with the solution of dissolved shear thickening gel (STG) in xylene. Following the evaporation of the solvent, STG applied carbon fabrics (SACFs) were placed according to the specified stacking sequence and impregnated with epoxy resin to manufacture the SACFRP laminates using the hot-press moulding technique. Different from existing works of STG-based flexible composites, this study firstly fabricated STG-based rigid fibre-reinforced composite laminates for load-bearing and impact-resistant applications. Results of SEM analysis revealed a strong bonding performance between carbon fibres and STG in SACF and SACFRP composites. Static tensile tests of transversely orientated UD SACFRP demonstrated an approximate 147 % increase in specific toughness relative to the reference CFRP equivalent. The reduced deflection and significantly decreased integrity loss of SACFRP laminates under 35 J LVI indicated their superior impact-resistant performance compared to its reference CFRP counterpart. The impact process analysis demonstrated the difference in the resistance mechanisms between SACFRP and its reference CFRP laminates under LVI. SACFRP laminates resist impact loads primarily via the flexural deformation, whereas the impact energy is principally absorbed by the damage to the reference CFRP laminates. Therefore, the novel SACFRP developed in this study, due to its enhanced toughness and impact performance, possesses considerable potential for structural applications under extreme impact loading conditions.