Size Effects on the Three‐Point Bending and Energy Absorption Performance of Pseudo‐Ductile Carbon/Glass Fiber Hybrid Laminates

ABSTRACT The brittleness of fiber‐reinforced polymer composites (FRPs) makes it difficult to balance their strength and toughness, resulting in no nonlinear warning phenomenon like metal materials before ultimate failure. By optimizing the fiber hybrid proportion, the damage mechanism of the FRPs can be effectively changed, enabling them to exhibit a nonlinear progressive damage process similar to that of metals, namely pseudo‐ductility. In this study, carbon/glass fiber hybrid (C/G) laminates with pseudo‐ductility characteristics were prepared by discontinuous thin‐ply carbon fiber prepreg and standard‐thickness glass fiber prepreg. Through experiments and numerical simulations, the size effects on the three‐point bending and energy absorption performances of C/G laminates were analyzed. With the increase in thickness, the failure load of C/G laminates under three‐point bending increased by 19.25%, but flexural strength decreased by 21.17%. The main damage modes of the C/G laminates included shear damage and delamination, where shear damage was mainly concentrated in the bending area in the middle of the laminates, while delamination initiated at the C/G interfacial region near slits. Stress concentration at the slits caused a synergistic effect of delamination through the thickness direction, thereby leading to a reduction in bending strength. The numerical simulations of the mechanical responses in the three‐point bending test were consistent with the initial elastic stage and brittle failure phenomenon.