碳-芳纶混编三维编织复合材料拉伸性能实验研究

发布时间：2018-10-26 09:08

【摘要】：本课题设计并制备了碳纤维为轴纱,芳纶纤维为编织纱和芳纶纤维为轴纱,碳纤维为编织纱的混编三维五向和三维六向复合材料。采用数字图像相关(DIC)技术记录试样在轴向拉伸过程中的表面全场应变,通过相近纤维体积含量下碳纤维三维编织复合材料及芳纶纤维三维编织复合材料的对比实验,分析了混编方式和编织结构对碳-芳纶混编三维编织复合材料拉伸性能和损伤机理的影响。试样轴向拉伸实验结果表明,同种编织结构下,芳纶纤维和碳纤维分别为轴纱的混编三维五向和六向编织复合材料的拉伸强度和模量分别较芳纶纤维三维五向和六向编织复合材料的高-2.71%,10.14%,21.21%,28.86%和36.77%,62.68%,30.28%,74.26%。芳纶纤维和碳纤维分别为轴纱的混编三维五向和六向编织复合材料的断裂伸长率分别较碳纤维三维五向和六向编织复合材料的高34.38%,11.96%,51.09%和2.19%。同种混编方式下,碳纤维和芳纶纤维三维五向编织复合材料,芳纶纤维和碳纤维分别为轴纱的三维五向编织复合材料较对应三维六向编织复合材料的拉伸强度分别高出58.72%,59.29%,27.84%和36.15%;拉伸模量分别高出47.43%,36.28%,43.07%和27.23%;断裂伸长率则无明显趋势变化。泊松比受编织结构影响较大,受混编结构影响较小。同种混编方式下,碳纤维,芳纶纤维,芳纶纤维为轴纱和碳纤维为轴纱的三维五向编织复合材料的泊松比分别较对应三维六向编织复合材料的高293.75%,162.50%,228.57%和344.44%。各组典型试样的时间-纵向应变曲线均接近线性。全场纵向云图表明,试样应变分布整体呈均匀性,局部呈周期性。同时,试样的面内轴向应变分布受混编方式和编织结构的影响,同种编织结构下,编织纱为碳纤维的试样其应变似"点阵"分布状态,编织纱为芳纶纤维的试样其应变似"波浪线"分布状态。同种混编方式下,三维五向编织复合材料的表面应变沿表层编织纱交织点均匀分散分布,而三维六向编织复合材料的表面应变则整体上沿六向纱分布。试样拉伸断口和纵向剖面形貌观测结果表明,同种编织结构下,芳纶纤维的加入降低了断口的整齐度,改善了试样断裂过程中基体的开裂与脱落现象,但同时降低了整体纤维与基体的浸润程度。同种混编方式下,三维五向编织复合材料的断口为倾斜锯齿状,其内部损伤程度随距断口的距离增大而降低,损伤传播距离较大,而三维六向编织复合材料的断口为平齐断口,其内部损伤集中在断口附近,损伤传播距离较小。
[Abstract]:In this paper, three dimensional five and six dimensional composites with carbon fiber as axial yarn, aramid fiber as woven yarn and aramid fiber as axial yarn and carbon fiber as woven yarn are designed and fabricated. The full-field strain of the specimen during axial tension was recorded by digital image correlation (DIC) technique. The comparative experiments of three-dimensional braided carbon fiber composites and aramid fiber three-dimensional braided composites with similar fiber volume content were carried out. The effects of blending mode and braiding structure on tensile properties and damage mechanism of carbon-aramid three-dimensional braided composites were analyzed. The results of axial tensile test show that under the same braided structure, The tensile strength and modulus of the three-dimensional five-direction and six-direction braided composites with aramid fiber and carbon fiber respectively as axial yarns are higher than that of the aramid fiber three-dimensional five-direction and six-direction braided composites, respectively, and the tensile strength and modulus of the composites are higher than that of the aramid fiber three-dimensional five-direction and six-direction braided composites. 28.86 percent and 36.77 and 62.68, about 30.28and 74.26. The elongation at break of the blended three dimensional five and six direction braided composites of aramid fiber and carbon fiber respectively is 34.38% and 11.96% higher than that of the three dimensional five direction and six direction braided composites, respectively, and is 2.19% higher than that of the three dimensional five direction and six direction braided composites. Carbon fiber and aramid fiber three-dimensional five-direction braided composites in the same blending mode, The tensile strength of the three-dimensional five-direction braided composite with aramid fiber and carbon fiber as axial yarn is 58.72% and 36.15% higher than that of the corresponding three-dimensional six-direction braided composite, respectively. The tensile modulus was 47.43% and 27.23% higher than that of 36.28%, respectively, but the elongation at break had no obvious trend. Poisson's ratio is influenced greatly by braided structure and less by mixed structure. In the same blending mode, the Poisson's ratio of three dimensional five-direction braided composites with carbon fiber, aramid fiber as axial yarn and carbon fiber as axial yarn is 293.7575 and 162.50 higher than that of three-dimensional six-direction braided composite, respectively. 228.57% and 344.44%. The time-longitudinal strain curves of each group of typical samples were almost linear. The full-field longitudinal cloud image shows that the strain distribution of the sample is uniform and the local strain distribution is periodic. At the same time, the in-plane axial strain distribution of the sample is affected by the mixing mode and the braiding structure. Under the same braiding structure, the strain distribution of the sample with the same braided yarn is like "lattice". The strain of the woven yarn as aramid fiber is similar to the "wave line" distribution. In the same blending mode, the surface strain of the three-dimensional five-direction braided composite is distributed uniformly along the interwoven point of the surface braided yarn, while the surface strain of the three-dimensional six-direction braided composite is distributed along the hexagonal yarn as a whole. The results of tensile fracture and longitudinal profile observation show that the addition of aramid fiber reduces the uniformity of fracture surface and improves the cracking and shedding of the matrix during the fracture process of the specimen under the same braided structure. At the same time, the wetting degree of the whole fiber and matrix was reduced. In the same blending mode, the fracture surface of the three-dimensional five-direction braided composite is inclined serrated, and the internal damage degree decreases with the distance from the fracture surface to the fracture surface, and the damage propagation distance is larger, while the fracture surface of the three-dimensional six-direction braided composite is flat and uniform. The internal damage is concentrated near the fracture surface, and the damage propagation distance is relatively small.
【学位授予单位】：天津工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TB332

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