碳纤维三向织物/环氧树脂复合材料的制备与力学性能

选择不同纱线间距即二经(纬)纱之间的中心距]尺寸的碳纤维三向织物, 采用热压成型技术制备了碳纤维三向织物/环氧树脂复合材料. 研究了纱线间距及样品裁剪角度等对力学性能的影响, 并与碳纤维二向织物/环氧树脂复合材料的力学性能进行对比. 结果表明, 随着纱线间距尺寸从2 mm增加到6 mm, 0°方向断裂强度从221.7 MPa下降到148.1 MPa, 撕裂强力从1000 N下降到600 N; 90°方向断裂强度从50.0 MPa下降到22.1 MPa, 撕裂强力从330 N下降到100 N; 顶破强力从424 N下降到216 N. 这些力学性能的逐渐降低是单位面积的碳纤维增强体含量减少和织物的孔洞增大共同作用的结果. 纱线间距为2 mm的碳纤维三向织物复合材料在0°(以纬纱为基准), 30°, 45°, 60°和90°方向的断裂强度分别为221.7, 48.5, 44.3, 227.7和50.0 MPa, 即断裂强度在0°和60°方向大于在30°, 45°及90°方向. 由三向织物的编织原理可知, 0°与60°方向完全相同, 因此其断裂强度相似, 且样品中有一组纱线与外加载荷平行, 对形变破坏具有一定的约束作用, 而30°, 45°和90°方向样品中三组纱线所在的方向均和外加载荷存在一定的夹角, 有效分散外加载荷的能力减弱. 对比碳纤维三向织物/环氧树脂复合材料与碳纤维二向织物/环氧树脂复合材料的断裂强度、 撕裂强力和顶破强力发现, 前者的综合性能明显优于后者, 碳纤维三向织物/环氧树脂复合材料的断裂强度、 撕裂强力、 顶破强力分别为221.7 MPa, 1000 N和424 N, 三向织物的优势得到凸显, 为后续制备多种类型的碳纤维三向织物复合材料及应用奠定了基础.

Preparation and Mechanical Properties of Carbon Fiber Triaxial Woven Fabric/Epoxy Composites

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.