Fig. 5
Impact properties of composites. a Impact force–time curves of the CFRP, SFRP and the HFRP composites with different hybrid ratios. b Impact force–time curves for HFRPs with different stacking sequences. c Impact strength of the epoxy resin as compared with that of the various CFRP, SFRP and HFRP composites with different hybrid ratios and stacking sequences. d Schematic force–time curve for the impact process; Ei and Ep represent the areas under the curve for the crack initiation and propagation stages of fracture (see text for explanation). e Absorbed energy Ei and Ep, ductility index (DI) of the CFRP, SFRP and HFRPs for the impact process. f Comprehensive evaluation of impact properties (impact strength, maximum load and ductility index) of CFRP, Ap-SFRP and 5C5S-1. The error bars represent the standard deviation of measured means
