基于典型微结构特征的三维编织C/C复合材料力学行为研究

Carbon fiber reinforced carbon matrix composites, the so called carbon/carbon (C/C) composites. Their small thermal expansion coefficient and good strength retention at high temperature, high specific strength and elastic modulus, as well as high thermal shock resistance make them primary materials for aerospace and military applications. Differing from the fiber reinforeced resin based composites, the analysis on mechanical behavior of 3D C/C composites is more complicated due to its inherent interface cracks and voids in matrix. .In this subject, the meso- and micro-structures of 3D woven C/C composites will be examined in detail by using PLM, SEM and high resolution Micro-CT nondestructive testing technology. Some scientific methods will be established to acquire the in situ properties of component materials (fiber bundle, matrix and interface) of the C/C composites. Based on the above information, the purpose of this subject is to establish a micromechanics analysis model of the 3D C/C composites, which is able to deal with the bundle/matrix debonding, inter-bundle cracks and voids. The objectives are to predict the stiffness performance of the C/C composites and to simulate its damage evolution behavior using the mesoscopic damage theory. The investigation of this subject will lay the foundation for evaluating the 3D woven C/C composites instrinsic properties scientifically and accurately.

C/C复合材料因比强度高、比模量高、高温下强度保持率高、较低的热膨胀系数，以及优异的抗热冲击性能而成为航天、军事领域热防护结构的主要备选材料。不同于树脂基纤维增强复合材料，C/C复合材料固有的界面裂纹和基体孔洞等微结构特征给其力学性能的准确把握带来极大挑战。本项目以三维编织C/C 为研究对象，通过传统显微观测和高分辨Micro-CT的运用获得其原位、无损的细微观结构信息，结合科学表征获得的材料组分材料(纤维、基体和界面)原位性能数据，建立能真实反映界面裂纹、基体孔洞等典型微结构特征的三维编织C/C复合材料细观结构模型，结合有限元方法数值预报整体材料的刚度性能。进一步建立组分材料的细观损伤模型和失效判据，数值模拟三维编织C/C复合材料的损伤演化及失效行为。本研究旨在为国内三维编织C/C复合材料的设计改进和工程应用奠定理论基础。

本项目以一种三维编织C/C复合材料为研究对象，通过传统显微观测和高分辨Micro-CT的运用获得了其原位、无损的细微观结构信息，结合科学表征获得的材料组分材料(纤维、基体和界面)原位性能数据，建立了该C/C复合材料三维有限元分析模型，该模型能有效预报材料的整体刚度性能，数值预测结果与实验结果有较好的一致性。最后通过简单应力、复杂应力状态下的编织C/C复合材料宏观力学行为的实验研究，定性分析了该材料的损伤演化及失效行为。截至目前，课题相关工作已发表期刊论文7篇，会议论文1篇，撰写GF报告1篇，其中SCI收录3篇，EI收录1篇，中文核心期刊3篇。