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To meet sustainability objectives in the transport sector, natural fiber (NF) and recycled carbon fiber (RCF) have been developed, although they have been typically limited to low to medium performance components. This work has considered the effect of interlayer hybridization of woven NF and non-woven RCF with woven virgin carbon fibers (VCF) on the mechanical and damping performance of hybrid laminates, produced using double bag vacuum infusion (DBVI). The mean damping ratio of the pure laminates showed a trend of NF>RCF>VCF, which was inversely proportional to their modulus. The tensile, flexural and damping properties of hybrid laminates were dominated by the outermost ply. The VCF-RCF and VCF-NF hybrid laminates showed a comparatively greater mean damping ratio. The results of this work demonstrate a method for the uptake of alternative materials with a minimal impact on the mechanical properties and improved damping performance. [ABSTRACT FROM AUTHOR]

Carbon fibre epoxy composites are sought after for their excellent specific energy absorption (SEA) but are costly. A range of prepreg carbon fibre epoxy layups were subjected to a 10 m/s impact with 4 kJ of energy. Fibre volume fraction and voidage were determined for each sample and the fracture analysed in detail. SEA ranged from 35.27 J/g to 60.25 J/g with the highest performance from 8 plies of 200 gsm 2 × 2 twill all laid at 0°. Vacuum assisted oven cure resulted in higher voidage than autoclave cure (2.52% versus 0.17%) but did not affect SEA. According to a ratio of performance to cost the highest rated samples were an 8 ply oven cure and a 3 ply autoclave cure specimen and there was little difference between them. This work has highlighted that there is enormous potential for cost reduction of prepreg carbon fibre epoxy energy absorption structures through the use of heavier areal weight fabrics and fewer plies as well as through the use of oven cured prepreg. [ABSTRACT FROM AUTHOR]

Abstract: Natural fibre composites represent an environmentally sustainable alternative to conventional glass and carbon fibre composites. Fibres derived from plants are renewable and have low levels of embodied energy compared to synthetic fibres. They are also low cost, low density, have high specific properties, are non-abrasive and less harmful during handling. In motorsport the front and rear impact structures are required to act as both load-bearing members and energy absorption devices. The requirement to absorb large amounts of energy means that the specific energy absorption (SEA) of the material is critical to maintaining a low mass. This work focuses on the potential for natural fibres to replace synthetic fibres for future environmentally friendly energy absorption structures. Conical test specimens of jute, flax and hemp were manufactured using vacuum assisted resin transfer moulding (VARTM) and subjected to impact testing. The natural fibre cones exhibited high values of SEA: unwoven hemp 54.3J/g, woven flax 48.5J/g and woven jute 32.6J/g. The SEA was influenced primarily by fibre volume fraction (Vf) where a high Vf leads to high SEA. Significant variability in SEA resulted from the variation in fibre strength and Vf as a result of the VARTM manufacturing process. Natural fibre composites have the potential to be widely applied as low cost, sustainable energy absorption structures. [Copyright &y& Elsevier]