Defects and Damage in Ceramic Matrix Composites (CMCs) - Implications for Component Life Prediction

ABSTRACT: The goal of the proposal is to develop life-prediction methodology and associated software for a damage-based non-linear deformation model to study the effect of manufacturing defects and service-induced damage in Ceramic Matrix Composites (CMCs). Once developed and thoroughly validated, the methodology would be used in cost effective development of CMC components by the Air Force and its major aerospace engine suppliers. The proposed methodology is based on a mechanistic (physics-based) model that includes direct consideration of defect and damage mechanisms, and environmental degradation relevant to CMCs. In Phase I the feasibility of using methodology to model effect of defects and to do life prediction of CMC materials has been demonstrated by comparison with limited amount of experimental data. The proposed Phase II effort aims to extend the applicability of the model to a variety of conditions relevant to aircraft operating conditions. The resulting enhancements will be experimentally validated and demonstrated. BENEFIT: Due to the proliferation in potential applications of ceramic matrix composites in military and commercial aerospace engines and in industrial gas turbine industries, the proposed dual-use high technology product has an immediate and expanding market. One benefit of the proposed product is in improving the process of evaluation of as-manufactured CMC parts to sufficiently meet desired structural life. The proposed product will also be useful in in-service component inspection and evaluation to estimate residual life. SAI will market the methodology, the software and technical expertise (services) to these and other industries.