Tensile and bending properties of biaxial weft-knitted and cross-ply thermoplastic composites

In this study, within the scope of experiments, two kinds of biaxial weft-knitted (BWK) fabrics with aramid (AR) and polyamide 66 (PA66) stitch fibers were used as reinforcement systems to fabricate thermoplastic composites with PA66 resin yarn. Then final composite became BWK with AR stitch yarn and cross-ply. The mechanical properties of composites were investigated by conducting tensile and three-point bending tests on specimens. In all specimens, PA66 was commingled with AR yarn. AR was used as reinforcement. In preliminary studies, AR unidirectional composites with AR/PA66 commingled fibers and with various twisting angles were produced and appropriate twisting angle was found by conducting tensile and three-point bending impact tests on specimens. Because of the higher volume fraction of the cross-ply composites, tensile and three-point bending properties of the cross-ply composite structures had higher than the BWK composites with the AR stitch yarn.