Analysis and Modeling of Foreign Object Damage (FOD) in Ceramic Matrix Composites (CMCs)

A significant barrier to the insertion of ceramic matrix composite (CMC) materials into advanced aircraft engines is their inherent lack of toughness under foreign object Damage (FOD) as well as post FOD. Our team will develop and demonstrate a physics-based model for FOD/post FOD in CMC’s. The model will incorporate physical mechanisms associated with impact for two different CMC systems: a) matrix-dominated system and b) fiber-dominated system. Our methodology will address impact and post-impact of both “as-built” and “as-is” CMC’s. It will account for architecture (2D/3D-nano) and CMC manufacturing (layered thickness, void shape/size, interfacial strength, micro-crack formation) taking advantage of the strength and toughness enhancing effect of different length scales of CMC structure. The model will be incorporated into our commercial progressive failure analysis software GENOA, that integrates commercial FEA and enhances their accuracy limitation. It will be validated using available CMC impact test data from NAVAIR SiC/SiC and Oxide/Oxide for a range of FOD tests. We will determine the feasibility for performing impact tests with Acoustic Emission/Electrical Resistance monitoring as damage assessment and health monitoring techniques that relates to damage model and life prediction. In Phase II high temperature impact testing will be conducted to further validate our model.