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基于金相显微镜观测的针刺C/C复合材料细观结构,考虑材料内部纤维的真实分布,建立了针刺C/C复合材料单胞模型。采用Linde失效准则,考虑纤维渐进损伤对材料进行了刚度折减,通过引入周期性位移边界条件,对针刺C/C复合材料的拉伸破坏进行了有限元法(FEM)数值模拟,分析了单胞模型的渐进失效过程,并预测了材料的拉伸强度。开展了针刺C/C复合材料拉伸试验,采用扫描电子显微镜(SEM)观察了材料的断口形貌,数值预测结果与试验吻合良好。针刺C/C复合材料受拉伸载荷后发生准脆性断裂,拉伸应力-应变曲线呈双线性,0°无纬碳布发生纤维断裂和基体开裂破坏,90°无纬碳布出现横向基体劈裂,最终断裂发生在针刺纤维与面内无纬碳布交叉区域。
Based on the observation of the microstructure of acupuncture C / C composites by metallographic microscope, the C / C composite cell model of acupuncture was established considering the true distribution of the fibers inside the material. The Linde failure criterion was adopted to consider the stiffness reduction of the material with the gradual damage of the fiber. Finite element method (FEM) numerical simulation of the tensile failure of acupuncture C / C composites was carried out by introducing periodic displacement boundary conditions. Cell model of the progressive failure process, and predict the tensile strength of the material. The tensile test of acupuncture C / C composites was carried out. The fracture appearance of the material was observed by scanning electron microscope (SEM). The numerical results agree well with the experimental data. The acupuncture C / C composites undergo quasi-brittle fracture after tensile loading, the tensile stress-strain curve is bilinear, fiber fractures and matrix cracking at 0 ° latitude carbon cloth, the horizontal Matrix cleavage, the final fracture occurred in the acupuncture fibers and in-plane latitude carbon cloth crossing area.