Improving the delamination resistance of CFRP by stitching-a review

Delamination as a result of low-velocity impact loading is a major cause of failure in fibre-reinforced composites. This paper gives an overview of one technique, stitching, which can provide through-thickness reinforcement of a traditional 2D laminate, thus improving its resistance to delamination. Stitching significantly improves some mechanical properties such as the compression-after-impact strength of the brittle carbon-fibre-reinforced polymeric matrix. However, it may result in the degradation of others due to the creation of resin pockets or the breakage of in-plane fibres. The causes of delamination, the advantages and disadvantages of stitching to improve the delamination resistance and finally the necessary techniques of manufacture are examined.