A UNIFIED APPROACH TO COMPUTATIONAL MODELING OF CERAMIC MATRIX COMPOSITES UNDER HIGH-TEMPERATURE CREEP, FATIGUE, AND INITIAL QUASI-STATIC LOADING

A novel unified reduced order homogenization model for initial quasi-static, creep, and fatigue loading of SiC/SiC CMCs at high temperatures is proposed. Driven by a single set of parameters, the model can seamlessly transition between initial quasi-static, creep, and fatigue regimes while capturing the complex material response of SiC/SiC CMCs. The reduced order homogenization approach provides a robust and efficient computational platform for analyzing composite behavior. Continuum damage mechanics provides the basis for the initial quasi-static CMC behavior while a hybrid damage-viscoplasticity model with brittle-ductile failure drives the time-dependent material behavior. A temporal multiscale approach extends the spatial multiscale model into fatigue regime, avoiding the computational complexity of modeling each cycle individually. The model is verified on two SiC/SiC material system, S200H and GEA SMI, in both initial quasi-static and time dependent loading regimes.