【摘要】 高温氧化引起的性能退化是制约C/SiC陶瓷基复合材料在航空航天热端部件中应用的关键因素。为准确预测其氧化损伤演化机制与力学性能退化行为，本文基于数值模拟方法开展了系统研究。首先，基于Fick扩散定律与氧化反应特征，引入化学反应消耗项与损伤因子，构建耦合扩散–反应的氧浓度控制方程及氧化状态演化模型。基于COMSOL平台，模拟二维织物叠层C/SiC复合材料在650℃下分别氧化2 h、4 h、6 h的氧气浓度场与氧化损伤因子分布，揭示氧浓度在不同结构区域的传输规律与损伤演化特征。进一步结合连续介质力学与渐进损伤理论，提出刚度有限退化与连续退化耦合的损伤演化方法，并在ABAQUS平台预测材料在氧化后的拉伸响应。研究表明，数值模拟所得应力–应变曲线及剩余强度与试验结果吻合良好，误差均小于10%。本文为C/SiC复合材料在高温服役条件下的氧化后力学性能预测及工程应用提供了理论支撑与数值分析手段。更多还原

【Abstract】 High-temperature oxidation-induced degradation is a critical factor limiting the application of C/SiC ceramic matrix composites in aerospace thermal-structural components. To accurately predict the oxidation damage evolution and mechanical property degradation of such materials, a systematic numerical study is conducted in this work. First, based on Fick’s diffusion law and the characteristics of oxidation reactions, chemical consumption terms and damage factors are introduced to establish a coupled diffusion–reaction oxygen concentration equation and an oxidation state evolution model. Using the COMSOL platform, the oxygen concentration field and oxidation damage factor distributions of a two-dimensional woven C/SiC composite subjected to oxidation at 650 ℃ for 2 h, 4 h, and 6 h are simulated, revealing the spatial-temporal distribution and evolution of oxygen in different structural regions. Subsequently, by integrating continuum mechanics with progressive damage theory, a coupled stiffness-degradation model incorporating limited and continuous degradation is developed, and the post-oxidation tensile response is predicted using the ABAQUS platform. The simulation results show good agreement with experimental data in terms of stress–strain behavior and residual strength, with a maximum error below 10%. This study provides theoretical support and numerical tools for evaluating the postoxidation mechanical performance of C/SiC composites under high-temperature service conditions.更多还原