Design, fabrication, and burner rig testing of three-dimensional woven ceramic matrix composite flanged hoop subelements

Ceramic matrix composites (CMCs) have been identified as a key material system for improving the thrust-to-weight ratio of high-performance aircraft engines. An interturbine flow-path duct for a high-performance engine has been identified as a component with the potential for 100% reduction in active cooling air and 80% reduction in weight through the use of CMC material systems. To reduce risk prior to incorporating the interturbine duct in a high-performance engine, a CMC subelement design was conducted, parts were fabricated from two potential CMC material systems, and tests were conducted in a National Aeronautics and Space Administration (NASA) high-temperature, high-pressure burner rig with parameters representative of the highperformance engine environment. The burner rig testing verified the mechanical attachment and flow path sealing techniques as well as distinguished the oxidative stability of the two CMC material systems tested. After the burner rig testing was completed, the successful subelements were laser cut into three continuous hoop configurations and tested at room temperature for hoop retained tensile strength. The retained strength test results as well as fractography work indicated the need for regional architecture modifications as well as improved methods of infiltrating the fiber tows with oxidation inhibitors.