Dynamic tensile properties of carbon/glass hybrid fibre composites under intermediate strain rates via DIC and SEM technology

Abstract

Carbon/glass hybrid fibre-reinforced plastic (C/GFRP) can effectively reduce product costs in manufacturing; however, its dynamic tensile properties remain unclear. In this study, the mechanical characteristics of C/GFRP and glass-fibre-reinforced plastic (GFRP) laminates were investigated using an HTM5020 high-speed tensile tester, digital image correlation (DIC), and scanning electron microscopy (SEM) at intermediate strain rates. Six strain rates (1, 10, 100, 250, 500 and 800 s−1) followed by three stacking sequences ([C2,G3,C2]s, [G3,C2,G3]s and [G8]s) were developed. The failure mechanism of C/GFRP under intermediate strain rates was identified using stress–strain curves, DIC sub-images, and macro/micro failure modes. Additionally, the variation laws for fracture strain, elastic modulus, and dynamic tensile strength of C/GFRP were examined. In response to an increase in strain rate, the strength and fracture strain of [C2,G3,C2]s increased by 36.6% and 142.9%. The elastic modulus [G3,C2,G3]s increased by 41.8%. Hybrid laminates are prone to interlaminar failure, resulting in lower strength and higher strain-rate sensitivity. Adding a carbon fibre-reinforced plastic layer effectively improves the stiffness of the laminates. A stiffness prediction formula for C/GFRP is proposed.