A Progressive Oxidative Damage Model of C/SiC Composites under Stressed Oxidation Environments

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.