三维编织C/SiC复合材料弹性常数预报

基于纤维倾角模型 ,根据层合板理论推导出其弹性常数计算公式。三维编织C/SiC复合材料不同于树脂基复合材料 ,一是纤维模量低于基体模量 ,二是碳纤维在高温沉积热解碳和碳化硅后模量有较大幅度的下降 ,还有较多的空洞存在。考虑到这些因素对三维编织C/SiC复合材料弹性性能的影响 ,编制了相应的C语言计算程序 ,预报了三维编织C/SiC复合材料的纵向弹性性能 ,对程序计算结果进行了分析讨论。另外 ,通过力学实验来验证了理论分析的可靠性。

Prediction of the Elastic Constants of 3-D Braided C/SiC Composites

The geometric structure of the 3 D braided composites are researched, based on which the unit cell (the obliquity model) is built. According to the theory of layer board we can obtain equations to calculate the elastic constants. The ceramic matrix composites differ from the resin matrix composites. Firstly, the modulus of fiber is lower than that of matrix.Secondly, the modulus of carbon fiber has much drop after being sedimentated by pyrolytic carbon and pyrolytic silicon carbon at high temperatures. Finally, much cavity lies without forecast. To a certain extent, these factors influence the elastic capability of the 3 D braided C/SiC composites. The relevant computer procedure is programmed that can predict the elastic constants of the 3 D braided C/SiC composites. The results are analyzed and discussed. In addition, mechanical experiments are done that validate the dependability of theoretic analysis.