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

The Phase II STTR technical objective will update, expand, and validate the excellent results achieved in the Phase I"Analysis and Modeling of Foreign Object Damage (FOD) in Ceramic Matrix Composites (CMC"s)"program. The program will evaluate CMC component life capability before and after impact in a realistic operating environment. Predictions will be validated using new experimental impact results at elevated temperatures and NDE measurements of CMC specimens before and after impact. Multi-scale Progressive Failure Analysis (MS-PFA) will use the GENOA commercial software coupled with LS-DYNA/ABAQUS to assess the micromechanical multisite damage evolution process. Updated models will include triangulation, adaptive meshing, microstructure and damage visualization, interface influences, etc. Damage and stress are fully visualized down to the micromechanical level, and show fiber/matrix/ply stress redistribution after damage. Delamination initiation/propagation and damage size versus impact velocity between specific plies will be compared to test results. A high temperature impact test facility and advanced NDE measurement capability will be developed at the University of Akron. Example materials under evaluation are MI SCi/SCi, NASA N24A and S200. Life prediction in an engine environment will be demonstrated before and after impact in a Phase II Option. Close coordination will be maintained with the NAVAIR TPOC.