【作者】 聂荣华； 矫桂琼； 王波；

【Author】 NIE Rong-hua,JIAO Gui-qiong,WANG Bo (Department of Engineering Mechanics,Northwestern Polytechnic University,Xi’an 710072)

【机构】 西北工业大学固体力学系；

【摘要】 根据二维编织C/SiC复合材料的细观结构及其制备工艺特点,提出了一种预测该材料编织布厚度方向热传导系数的单胞模型。模型简化了编织结构纱线的实际构型,充分考虑了编织结构复合材料由于CVI工艺制备陶瓷基复合材料产生的孔洞对热传导系数的影响。考虑了编织布叠层顺序对叠层厚度热传导系数的影响,得到了二维编织C/SiC复合材料的厚度方向热传导系数的范围。利用单胞模型预测了二维编织C/SiC的结构参数、纤维体积含量、孔洞含量对复合材料厚度方向热传导系数的影响规律,结果表明:随着纤维束扭结处产生间隙与纱线宽度比值的增大,厚度方向热传导系数减小;当其他参数不变时,随着纤维体积含量的增大,厚度方向热传导系数反而下降;随着孔洞体积含量的增加,厚度方向热传导系数也出现了下降的趋势。利用Hotdisk热测量仪采用瞬变平面热源法测试了二维编织C/SiC复合材料沿厚度方向和面内的热传导系数,试验结果与模型预测结果吻合较好。更多还原

【Abstract】 A unit cell model based on meso-structure and fabrication procedure is presented for the out-of plain and in-plain coefficient of thermal conductivity of 2-D braided C/SiC composites.In this unit cell model,the actual strand cross-section geometry are simplified and the void caused by possible gap between two adjacent strands are taken into account.meanwhile,the difference Knit cloth nappe are taken into account,the range of out-of plain coefficient of thermal conductivity were gained.The influence of structure parameters on 2-D braided C/SiC composites’ coefficient of thermal conductivity was predicted.The predicted results show that composites’ out-of plain coefficient of thermal conductivity decrease with increase of kinking distance,as well as,decrease with increase of void volume fraction.out of plain coefficient of thermal conductivity also decrease with increase of fiber volume fraction.Test result shows that there is a good correlation between the predicted results and the experimental values.更多还原