Repair of Ceramic Matrix Composite Structures

The overall objective of this Phase II effort is to conduct an operational evaluation of a repaired Ceramic Matrix Composite (CMC) component, such as a gas path liner for an advanced F119 exhaust nozzle. CMC repair methods developed in Phase I will berefined and extended to cover three levels of damage: 1) surface ply loss, 2) delaminations and ply rupture, and 3) through-hole damage. The Phase II repairs will be evaluated based on survivability in an engine environment, applicability to various levelsof damage, electromagnetic performance, and level of effort, cost and schedule required to perform the repair. A building block approach will be used for the development, design and analysis of the repairs, starting at the coupon level and thensub-component level to prepare for component level implementation. Repair methodologies will be matured in coordination with a Component Design Review Committee to establish the acceptance requirements necessary to qualify a repaired component for engineoperation. Full-scale component repairs and evaluation will undergo assessment by a Critical Design Review prior to testing of a repaired component in a Pratt & Whitney F119 engine under AFRL's High Durability Hot Exhaust Structure Dual Use Science andTechnology (DUS&T) program.