考虑孔隙和微裂纹缺陷的C/C-SiC编织复合材料等效模量计算
Numerical computing of effective modulus of woven C/C-SiC composites including porosities and micro-cracks
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摘要: 通过观察C/C-SiC复合材料组元分布的扫描电子显微镜(SEM)照片 , 获得了C/C-SiC复合材料化学气相渗透(CVI)制备过程中产生孔隙和微裂纹的几何信息。在此基础上 , 建立了包含孔隙和微裂纹的C/C-SiC微结构有限元模型 , 并利用均匀化等效计算方法预测了平纹编织C/C-SiC复合材料的模量。针对CVI沉积方式制备的2组不同的C/C-SiC复合材料 , 实验测试与等效计算结果表明 : 基于 SEM照片建立的C/C-SiC纤维束和复合材料微结构有限元模型 , 能够反映CVI工艺制备C/C-SiC中孔隙和微裂纹的分布状况; 计算结果与实验数据有良好的一致性 , 数值计算可有效预测C/C-SiC编织复合材料的模量。Abstract: The woven carbon fiber reinforced C-SiC binary matrix (C/C-SiC) composite manufactured by chemical
vapor infiltration (CVI) method was investigated. Based on the material tomography of scanning electron microscopy (SEM) , distributions of porosities and micro-cracks were identified and included in the finite element model of C/C-SiC composites. The homogenization method was used for the evaluation of effective modulus of woven C/C-SiC composites. The results of the numerical computing and experimental tests were compared for two cases of C/C-SiC composites with different layer thickness. It is shown that the proposed finite element models of C/C-SiC can characterize physically the real situation of the involved porosities and micro-cracks related to the CVI process. The numerical results of effective modulus agree reasonably with the experimental ones.
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