A progressive oxidative damage model of C/SiC composites, which is based on the oxidation mechanism and mechanical model of C/SiC composites, is presented to simulate the damage process of C/SiC composite under stressed oxidation environments. Firstly, the oxidation failure time of fibers was calculated according to the fiber stress and the fiber strength decline rule under stressed oxidation environments. Secondly, the stress redistribution and crack propagation around fracture fibers were given by combining the fracture position of fibers with the mechanical model, and the crack propagation would cause more fibers to be oxidized. Thirdly, the progressive oxidative damage process of C/SiC composites under stressed oxidation environments was simulated by repeating the cyclic process of fiber oxidation fracture and crack propagation around the fracture fibers. Finally, through the progressive oxidative damage model, the stress-strain curves and fracture morphology of the unidirectional C/SiC composites after stressed oxidation were predicted. The simulation results were correlated well with the experimental results, in terms of stressed oxidation life, stress-strain curve and variation law of fracture morphology, which indicated the reliability of the model.

基于C/SiC复合材料的氧化机理和力学模型，提出了一种C/SiC复合材料渐进式氧化损伤模型，模拟了C/SiC复合材料在应力氧化环境下的损伤过程。首先，根据应力氧化环境下的纤维应力和纤维强度下降规律计算纤维的氧化失效时间。其次，结合纤维的断裂位置和力学模型，给出了断裂纤维周围的应力重新分布和裂纹扩展，裂纹扩展会导致更多的纤维被氧化。第三，通过重复纤维氧化断裂和断裂纤维周围裂纹扩展的循环过程，模拟了应力氧化环境下C/SiC复合材料的渐进氧化损伤过程。最后，通过渐进氧化损伤模型，预测了应力氧化后单向C/SiC复合材料的应力-应变曲线和断裂形貌。模拟结果与实验结果在应力氧化寿命、应力-应变曲线、断口形貌变化规律等方面具有较好的相关性，表明模型的可靠性。