连续碳化硅纤维增韧陶瓷基复合材料微结构数字化建模和宏观各向异性模量预测

Digital Modeling of the Natural Microstructures and Evaluation of the Overall Anisotropic Moduli of Ceramic Matrix Composites Toughened by Continuous SiC Fiber Bundles

围绕陶瓷基复合材料连续增韧相各向异性难以快速建模和宏观模量精准预测困难的问题,本工作结合水平集法和有限元法建立了陶瓷基复合材料复杂微结构数字化自动建模方法及预制体不同区域材料各向异性赋值策略。同时,以二维SiC编织布增韧陶瓷基复合材料(SiC_(f)/SiC)为例,采用细观力学均匀化方法和自编程序实现了兼顾自然孔隙影响的连续纤维增韧陶瓷基复合材料宏观各向异性模量跨尺度准确计算。与已有文献中的SiC_(f)/SiC性能实验数据对比,验证了本工作中建模方法和模量计算算法的有效性。此外,本工作还探究了SiC_(f)/SiC自然孔隙形状及纤维束波纹度比对材料宏观性能的影响机制。

To properly overcome the difficulties in modeling the anisotropy of continuous toughening phases and in predicting the overall moduli of ceramic matrix composites,this work developed an automatic digital methodology for modeling the complex roughly periodic microstructures together with a convenient technique for assigning the anisotropic material properties of the relevant performs of ceramic matrix composites(CMCs)by combining the level set method and the finite element method.Meanwhile,the CMC toughened by the two-dimensional SiC woven fabric(SiC_(f)/SiC)was taken as an illustration to establish the multiscale computational strategy of accurately evaluating the overall anisotropic moduli of SiC_(f)/SiC taking account of the natural pore effects based on the micromechanics scheme and self-programming.The validity of the digital modeling methodology as well as the computational algorithm for predicting the overall modli of SiC_(f)/SiC in this study was demonstrated by comparing the numerical predictions with the experimental data in the open literature.Furthermore,the influence of the natural pore shapes and the waviness ratio of the fiber bundles were investigated in detail.