The influence of stitch architecture in multiaxial warp-knit fabrics on the damage tolerance and environmental durability of carbon fibre-reinforced composites

Among all the 3D textile reinforcements, Multiaxial Warp Knit (MWK) fabrics have brought together the advantages of textile technology: high deposition rates, unlimited shelf-life, lower cost and finally an improvement in the damage tolerance by the use of stitching. However, the stitching in MWKs is slightly different from that traditionally used, i.e. overstitching. The effect of this type of stitching has been investigated and is reported in this work. Three different variants of stitch architectures of carbon MWK, used in an epoxy matrix, were considered. Interlaminar shear strength, low energy impact, through penetration impact and compression strength testing were carried out on dry samples, while interlaminar shear strength, compression strength, DMTA, FTIR, Raman spectroscopic analysis were carried out on aged samples. [Continues.]