In order to overcome the roughness of the previously proposed micromechanical model [Acta Mech. Sin. (2011) 382], an enhanced multiscale analytical model was thus developed based on the rule of mixture, shear-lag theory and statistical approach to forecast the load carrying capacity of the prestressed ceramic matrix composites (CMCs) subjected to high-temperature oxidation. For comprehensive characterization of the mechanical degradation mechanisms, the oxidation induced fiber necking (or embrittlement) and fiber-matrix interface weakening were both taken into account. The suggested model was then applied to 2D-C/SiC composites. The influences of interface friction resistance, interface recession length, fiber necking factor and oxidation duration upon the residual mechanical property were investigated. Parametric analysis demonstrates that the modified formulations are much more reasonable than the previous model. The predicted residual tensile modulus and strength for the 2D-C/SiC composite agree well with the experimental data and furthermore the microscopic damage mechanisms were correlated properly with the macroscopic fracture morphologies.

为了克服先前提出的微机械模型的粗糙性[Acta Mech。罪。（2011）382]，因此，基于混合规则，剪切滞后理论和统计方法，开发了一种增强的多尺度分析模型，以预测承受高温氧化的预应力陶瓷基复合材料（CMC）的承载能力。为了全面表征机械降解机理，同时考虑了氧化引起的纤维颈缩（或脆化）和纤维-基质界面的削弱。然后将建议的模型应用于2D-C / SiC复合材料。研究了界面摩擦阻力，界面凹陷长度，纤维颈缩系数和氧化持续时间对残余力学性能的影响。参数分析表明，修改后的公式比以前的模型更合理。预测的2D-C / SiC复合材料的残余拉伸模量和强度与实验数据吻合良好，此外，微观损伤机理与宏观断裂形态也有相关性。