Mechanical behavior and failure mechanism of aerogel-reinforced carbon fibre/epoxy composites under quasi-static/impact loading

The improvement of the impact resistance of carbon fiber reinforced epoxy (CF/EP) composite is of great significance for its application in safety protection. Herein, an approach to improve the compressive mechanical properties of CF/EP composites by self-interlocking Ti₃C₂T_x/polyvinyl alcohol (PVA) aerogel (TPA) has been developed. Mechanical responses and strain rate effects of CF/EP and TPA/CF/EP composites in longitudinal, transverse and through-thickness directions under quasi-static/dynamic loading have been studied. The results show that the stitching effect of TPA leads to the fact that the fracture has been dominated by cohesive failure and fiber breakage. Compared with CF/EP composites, TPA/CF/EP composites exhibit higher compressive strength and Young's modulus in the strain rate range from 0.003 s⁻¹ to 2369 s⁻¹. TPA/CF/EP composites have different damage evolution under quasi-static and dynamic loading and exhibits obvious strain rate sensitivity. Moreover, high-speed camera photographs and micro-morphological characteristics show that TPA/CF/EP laminates have different failure modes and fracture mechanisms for different loading directions. The well understanding of fracture mechanism can strengthen people's capability of and offer insights into designing advanced energy-absorbing materials and structures.