Abstract:

The triaxial woven fabric exhibits better mechanical properties than the ordinary fabrics due to its high symmetric weaving structure and good isotropy which can distribute the stress more effectively. In this study, the carbon fiber triaxial woven fabric/epoxy composites with different center distance dimensions between two warp(weft) yarns were prepared by hot press forming technology. The influences of center distance dimensions between two warp(weft) yarns and cutting angles of the specimens on the mechanical properties were studied and demonstrated by comparing with carbon fiber biaxial fabric/epoxy composites. The results show that the fracture strength at 0° decreases from 221.7 to 148.1 MPa and the tearing strength decreases from 1000 to 600 N with the yarn spacing increasing from 2 to 6 mm. Meanwhile, the fracture strength at 90° decreases from 50.0 to 22.1 MPa, the tearing strength decreases from 330 to 100 N and the bursting strength decreases from 424 to 216 N. These reductions in mechanical properties are ascribed to the decrease in the carbon fiber content per area and an increase in the pores of the fabric. The fracture strength of carbon fiber triaxial woven fabric/epoxy composite with a yarn spacing of 2 mm at 0°(based on weft), 30°, 45°, 60° and 90° is 221.7, 48.5, 44.3, 227.7 and 50.0 MPa, respectively. Obviously, the fracture strength at 0° and 60° are much higher than those at 30°, 45°, and 90°. According to the weaving principle of the triaxial woven fabric, the specimens at 0° and 60° are completely identical, so the fracture strength at these two angles is similar. Moreover, specimens at 0° and 60° have a set of yarns parallel to the applied load, which can restrain the deformation damage to a certain extent. However, the three sets of yarns at 30°, 45° and 90° all have a certain angle with the applied load, so the ability to distribute the applied load is weakened. By comparing with the carbon fiber biaxial fabric/epoxy composite, it is found that the comprehensive performances(fracture strength, tearing strength and bursting strength) of carbon fiber triaxial woven fabric/epoxy composite are significantly better. The fracture strength, tearing strength, and bursting strength of the carbon fiber triaxial woven fabric/epoxy composite can reach up to 221.7 MPa, 1000 N, and 424 N, respectively. This study has highlighted the advantages of triaxial woven fabric and laid the foundation for the subsequent preparation of various types of carbon fiber triaxial woven fabric composites and their wide application.

Key words: Carbon fiber triaxial woven fabric, Epoxy resin, Composite, Mechanical property