Influence of interlaminar fracture toughness on impact resistance of glass fibre reinforced polymers

This work is concerned with delamination resistance of glass fibre reinforced polymers (GFRP) and its influence on GFRPʹs resistance to transverse, point impact. The study used two GFRP, one with polyurethane matrix and the other isophthalic polyester. The two GFRPs show distinctly different mode I delamination resistance. Under the same impact condition, at speeds from 1.5 to 5 m/s, the polyurethane-based GFRP developed a smaller damage size than the isophthalic polyester-based counterpart, suggesting that the former has higher impact toughness. However, the two GFRPs showed little difference in the total energy absorbed during the impact, which is another measure commonly used for impact toughness evaluation. We conclude from the study that a consistent trend exists between the delamination resistance in mode I and the critical force for the incipient impact damage. Difference of the impact resistance between the two GFRPs is mainly on the impact damage size developed. The total energy absorbed during the impact remains the same, which is independent of mode I delamination resistance of the GFRP.