Glass-Carbon hybrid veil interleaving to enhance fracture toughness and shear strength in glass epoxy composites: An experimental study

This study investigates the influence of hybrid veils interleaving on interlaminar fracture toughness (IFT) and interlaminar shear strength (ILSS) of glass-epoxy composites. The hybrid veils were prepared using a papermaking technique by varying weight percentage of carbon and glass fibers. The veil-interleaved and reference laminates were manufactured by the aid of hand layup technique. The double cantilever beam (DCB), end notch flexure (ENF), and short beam strength (SBS) tests were conducted to evaluate mode-I, and mode-II IFT, and interlaminar shear strength of the composite laminates. The results indicate that improved mode-I IFT during propagation was approximately equal to 15% for hybrid veil comprising of 20 wt% carbon fibers. Under mode-II loading, an improvement of about 42-96% was observed with respect to decreased carbon content from 50 to 20 wt%. The maximum enhancement of about 37% in ILSS was observed with hybrid veil loaded composite with 40 wt% of carbon fibers. Further, a scanning electron microscopy (SEM) examination was carried out on fractured samples to understand various failure mechanisms and their effects on improved IFT.