Ceramic Matrix Composites Condition Assessment and Damage Monitoring

Ceramic matrix composites (CMCs) have long been considered for high temperature application within the gas turbine engine, and some advanced designs now incorporate these. There is a strong commercial drive to implement CMCs into future civil engine designs, mainly as a means to increase engine operation temperatures, improve fuel efficiency and reduce greenhouse gas emissions.
The objective of the project is to explore techniques applicable for condition assessment and damage monitoring of CMCs. These potentially include methods such as microwave dielectric spectroscopy, dynamic modulus loss tangent (in conjunction with interrupted fatigue), process compensated resonance testing and terahertz imaging. In each case assessing the condition of test coupons with a view to sentencing parts at one shop visit for pass-on to a second service interval.
The use of X-ray Computed Tomography (CT) to understand how damage propagates in CMCs may improve understanding and help to inform the condition assessment techniques as well as understand the influence of material surface condition. Additionally, investigations into the difference in damage propagation characteristics of CMCs with design relevant architectures will complement the ongoing CMC research development programmes within Rolls-Royce plc.