Modelling high temperature progressive failure in C/SiC composites using a phase field model: Oxidation rate controlled process

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High-temperature oxidation damage in C/SiC composite, alongside mechanical failure, has becoming a focal point of developing high performance motor components. However, most of existing models focus on only one field and thus can hardly to simulate a complete process. To address this, a thermodynamically consistent phase field model tailored specifically for C/SiC composites is proposed. This model offers a long-desired capability to encompass both carbon fiber oxidation in oxidation controlled stage and mechanical fracture, as well as their intricate interactions. Instead of relying on predefined fields or empirical knowledge, our model determines the oxygen field distribution and the evolution of new cracks through the differential equations rigorously, thereby providing a more accurate estimation of the location and extent of the failure process. The validity and reliability of our model have been tested through a few numerical studies. The proposed model has successfully captured the intricate characteristics of micro-crack propagation in C/SiC composites, including the saturation of cracks originating from the SiC matrix and the fracture process of carbon fibers after oxidation. As a result, our research is anticipated to be serving as an invaluable foundation for quantitative investigations into the performance of C/SiC composites, paving the way for the development of more robust and reliable high-temperature C/SiC composites.