Abstract: The tensile properties of epoxy composites reinforced with carbon fiber weft inlay knitted fabrics were studied. In the experiment, the reinforcement ground structure is composed of double rib. By changing the number of lining yarn and the depth of the yarn in the weft lining, weft inlay knitted fabric with 4 different structures and parameters is knitted. Finally, the composite plate is prepared by hydraulic technology. The tensile strength and circle strength of carbon fiber were tested by universal strength testing machine. The tensile properties of composites at 0 degrees, 45 degrees and 90 degrees were tested. The results show that the strength of the composite material and the tensile modulus of elasticity are obviously enhanced in the direction of 90 degree after being inserted into the weft yarn, and the tensile curve is linear. The strength of 0 and 45 directions is decreased slightly, but the effect is not obvious. Moreover, as compared to the strength of composite material with different weft lining yarn numbers, the more the number of weft yarns inserted per unit length, the greater the strength at the 90 degree direction. The influence of different sinking depth on the properties of the composite is compared. The strength of the plate in the direction of 45 and 90 degree is reduced, and the strength in the direction of 0 degree increases with the sinking depth depter.

Key words: carbon fiber, weft knitting, weft inlay, tensile properties