Design of composite materials with improved impact properties

Composites have been widely used in applications where there is a risk of impact, due to the excellent properties these materials display for absorbing impact energy. However, composites during impact situations typically generate an enormous number of small pieces, due to the energy absorption mechanism of these materials, a mechanism which does not include plastic deformation. This can prove dangerous in sports competitions, where the small fragments of the original structure may harm competitors.This study was designed to explore the possibility of incorporating a material which, whilst maintaining a high level of energy absorption without any plastic deformation mechanism, was able to maintain its original form, or at least significantly reduce the number of pieces generated after impact.The addition of a polyamide layer, NOMEX®, to a monolithic fabric laminate was investigated in this paper. The process of fabrication is described and the different properties of the material under consideration: interlaminar fracture toughness energy (GIC), indentation (id) and delamination after impact (Ai) and compression after impact (σCAI), were measured and compared with those of the original monolithic fabric.