材料初始缺陷对平纹编织C/SiC复合材料热残余应力的影响研究

Study on the Influence of Initial Defects on Thermal Residual Stress of Plain Weave C/SiC Composites

C/SiC热残余应力影响材料服役性能,而初始缺陷影响热残余应力,因此有必要对平纹编织C/SiC复合材料的初始缺陷与热残余应力的关系进行研究。通过试样截面扫描电镜(SEM)图像对材料各类初始缺陷的分布特征进行测量和统计,建立含初始缺陷的宏观材料的代表体积单元(RVE)和纤维束RVE有限元模型;采用稳态变温法及有限元细观计算力学(FECM)方法预测含初始缺陷的纤维束RVE有效性能参数及热残余应力。结果表明:应力预测值与试验值吻合较好,得到了各类初始缺陷与宏观材料热残余应力之间的定量映射关系。

The thermal residual stress of C/SiC affects the service performance of the material,and the initial defects affect the thermal residual stress,so it is necessary to study the relationship between initial defects and thermal residual stress of plain weave C/SiC composites.The distribution characteristics of various initial defects of the material are measured and computed by scanning electron microscopy(SEM)image of the sample,and the representative volume unit(RVE)and fiber bundle RVE finite element model of the macroscopic material with initial defects are established.The steady change temperature method and finite element computational mechanics(FECM)method are used to predict the effective performance parameters and thermal residual stress of fiber bundle RVE with initial defects.The results show that the stress prediction values are in identical with test values,and the quantitative relationship between various initial defects and thermal residual stress of macroscopic materials are obtained.