Impact and post impact (CAI) behavior of stitched woven–knit hybrid composites

In this study, the effect of stitch pattern on the impact and post impact (CAI) behavior of eight ply woven–knit hybrid composite plates consisting of 2D woven fabrics as outer layers and rib knitted fabrics as inner layers was investigated. Layers of the woven–knit hybrid composite plates were sewed in circular, square and diamond shape through thickness in order to prevent delamination and slippage between the layers. Impact and post impact testing were carried out in order to determine the impact and post impact resistance of three different stitched composite structures. Results showed that the impact strength of composite laminate increased 5.5%, 11% and 22% in the case of square, diamond, and circular stitching, respectively. It was also found that the woven–knit hybrid composites with square pattern have the highest CAI strength.