单向C/SiC复合材料热残余应力数值模拟研究

连续纤维增韧陶瓷基复合材料制备过程中因纤维与基体线胀系数失配会产生热残余应力,从而导致纤维脱粘、基体开裂等现象,严重影响复合材料力学性能。本文针对CVI工艺制备的单向C/SiC复合材料,建立"纤维-界面-基体"单胞物理模型,基于细观力学分析方法对热残余应力分布规律进行预测,采用ABAQUS对材料制备过程进行数值模拟,揭示了界面厚度、纤维体积分数、制备温度等参数对纤维、基体热残余应力分布的影响规律,分析了热残余应力对复合材料力学性能的影响。研究结果能够为C/SiC复合材料的设计、分析及微纳力学性能试验提供理论支持。

Numerical Simulation of Thermal Residual Stresses For Unidirectional C/SiC Composites

During the preparation of continuous fiber-reinforced ceramic materials, the mismatch of linear expansion coefficient between the fiber and matrix may induce thermal residual stresses, which will result in fiber debonding and matrix cracking ultimately. And furthermore, it will have a significant influence on macro-mechanical properties. Based on the unidirectional C/SiC composites, this paper set a unit cell model of "fiber-interface-matrix" to predict the distribution rules of thermal residual stresses by micromechanics method. With ABAQUS software, the numerical simulation research on the preparation of C/SiC composites was developed, which revealed the influence rules of the interface thickness, fiber volume fraction and preparation temperature to the thermal residual stresses of the composites. And the effects of thermal residual stresses on mechanical properties of composites were also analyzed. The result is expected to provide a useful guideline for the design, evaluation and optimal application of C/SiC.