Mode I and II interlaminar fracture toughness of glass/carbon inter-ply hybrid FRP composites: Effects of stacking sequence and testing temperature

Abstract

Even though laminated FRP composites show exceptional performance in various modes of loading, they are susceptible to delamination. The ambient temperature and elevated temperature delamination resistance of glass/carbon fiber interply hybrid composites were assessed via mode I and mode II interlaminar fracture toughness tests performed at 30, 50 and 70°C. Interply hybrid composites performed better than composites with single type of fiber. The fracture toughness of inter-ply hybrid composites varied with the stacking position. At 30°C, mode I fracture toughness value of alternative glass and carbon fiber stacking sequence (G1C1)5 of hybrid composite showed 40% improvement over 10 layered carbon/epoxy (C10) composite. Further, Mode II fracture toughness of C5G5 composite showed 22% enhancement, and C10 exhibited 42% improvement over 10-layered glass/epoxy composite. Increasing the test temperature of all composites improved their GIC and GIIC values. The increment in the mode I fracture toughness properties of all composite was in the range of 5%–23% at 70°C from its room temperature value. The fractographic images of fractured samples were studied under a scanning electron microscope and failure mechanisms of composites were identified.