The low velocity impact response of auxetic carbon fibre laminates

Abstract

The low velocity impact resistance of auxetic carbon fibre laminates has been compared to that of laminates with matched through‐the‐thickness modulus, but with Poisson's ratios of near zero and positive values. Four impact loads corresponding to major events in the static indentation response were examined and damage was assessed by ultrasonic C‐scans, detailed fractography and measurement of residual properties. It was found that enhancements were seen in resistance to low velocity for the auxetic laminates, but only at low energy levels, indicating some degree of rate dependency. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Auxetic warp knit textile structures

“…A very wide range of materials can be fabricated in auxetic form including polymeric and metallic foams 2–5, polymers 6–9, fibre reinforced composite laminates 10–13 and honeycombs 14–17. A further consequence of auxetic behaviour is that many mechanical properties are predicted to be enhanced such as low velocity impact resistance 18, indentation 19 and shear 20. A new class of auxetic materials seeking to exploit these property enhancements is auxetic textile structures.…”

Mechanics of Advanced Materials

“…13a): when an impact loading is applied to them, the material generally moves away from the direction of loading, and the hardness is consequently lower than that of NPR materials. Supporting such theoretical considerations, the phenomenon has been validated by using many synthetic NPR materials: polymeric and metallic foams [96][97][98][99], fibre-reinforced composite laminates [100][101][102] and polymers [103][104][105][106].…”

“…However, the correlations are complicated, since the deformation mechanisms are also affected by delamination and inter-laminate shearing [109]. Besides simple quasi-static loading, behaviours of NPR materials under cyclic loading and varying strain-rate loadings were also investigated using both numerical and experimental methods [100,101,[109][110][111][112][113][114][115][116][117][118]. Generally, the obtained results indicate higher toughness of NPR composite materials than that of conventional ones.…”

An experimental study of thermal post‐production processing of auxetic polypropylene fibres

“…Apart from the unusual displacement behaviour, auxetic materials also benefit from other enhancements including fracture resistance [1][2][3], energy absorption [3][4][5] and double curvature [6]. Lakes [1] was the first to document the production of a synthetic auxetic material i.e.…”