Session: 02-01 Mechanical Behavior of Ceramics and Composites

Paper Number: 127571

127571 - Vibration and Acoustic Emission Assessment of a SiCf/SiC Ceramic Matrix Composite With Damage 

SiC_f/SiC Ceramic Matrix Composites (CMCs) offer a considerable advantages over existing metallic systems employed in hot section components in the gas turbine engine. However, due to their complex structure there are a number of damage modes that can occur under mechanical loading, such as matrix cracking, interfacial cracking and fibre failure. Therefore, there is a requirement for test methods, that are in-situ and ex-situ, to help understand these damage modes, in terms of how and when they take place and what they mean relative to material condition.

The aim of this paper is the analysis of vibration response of undamaged and damaged SiC_f/SiC CMC material. Cantilever beam vibration experiments were conducted before and after a series of mechanical loading conditions. Resonant frequency values were extracted using the Fast Fourier Transform (FFT) and compared, revealing a correlation between changes in natural frequency relative to the undamaged material, and the mechanical loading level, thus a correlation with the level of damage in the CMC. In addition, a series of acoustic emission (AE) experiments were carried out at the same mechanical loading levels, to support understanding of the damage mechanisms taking place in the CMC. As a result, vibration experiments could potentially offer an alternate non-destructive evaluation (NDE) technique to assess the condition of CMC material.

Presenting Author: Spencer Jeffs Swansea University

Presenting Author Biography: Dr Spencer Jeffs is a member of the Aerospace Department at Swansea University and is based in the Institute of Structural Materials as part of the Materials Research Centre.

Dr Jeffs' research interests align predominantly to the fundamental characterisation of materials for gas turbine applications, including titanium alloys, nickel base superalloys, advanced high strength steels and ceramic matrix composite material systems investigating relationships between processing, microstructure and properties. Research is conducted employing a range of advanced experimental, analytical and computational techniques including mechanical and miniaturised testing, electron microscopy and X-ray CT alongside close collaboration with industrial and academic partners.

Authors:

Spencer Jeffs Swansea University
Jordan Stephen Swansea University
Zak Quiney Swansea University
Gonzalo García Luna Rolls-Royce plc