二维编织SiC/SiC陶瓷基复合材料宏观弹性常数预测及模态试验研究

In order to study vibration characteristics of 2-D braided SiC/SiC ceramic matrix composites, the method to predict macroscopic effective elastic constants was established, on the basis of which modal analysis and experimental verification were performed on the composite flat coupons. First, in accordance to the architecture characteristics of the 2-D braided SiC/SiC ceramic matrix composites, the unit cell model featured with cubic B splines and sine curves was established. Then, its macroscopic effective elastic constants were predicted in the framework of micromechanical finite element analysis. The predicted elastic modulus has a relative error less than 3% compared with the experimental data in relevant literature. In the end, hammer model test was carried out on the 2-D braided SiC/SiC ceramic matrix composite flat coupons. The finite element predicted frequencies of the first five vibration modes had relative errors less than 4% compared with test results.