Fatigue lifetime of ceramic matrix composites at intermediate temperature by acoustic emission
Résumé
The fatigue behavior of a Ceramic Matrix Composite (CMC) at intermediate temperature under air is investigated. Because of the low density and the high tensile strength of CMC, they offer a good technical solution to design aeronautical structural components. The aim of the present study is to compare the behavior of this composite under static and cyclic loading. Comparison between incremental static and cyclic tests shows that cyclic loading with an amplitude higher than 30% of the ultimate tensile strength has significant effects on damage and material lifetimes. In order to evaluate the remaining lifetime, several damage indicators, mainly based on the investigation of the liberated energy, are introduced. These indicators highlight critical times or characteristic times, allowing an evaluation of the remaining lifetime. A link is established with the characteristic time around 25% of the total test duration and the beginning of the matrix cracking during cyclic fatigue. © 2017 by the authors.
Mots clés
Acoustic emissions
Ceramic materials
Ceramic matrix composites
Cyclic loads
Service life
Tensile strength
Characteristic time
Fatigue lifetime
High-tensile strength
Intermediate temperatures
Static and cyclic test
Structural component
Technical solutions
Ultimate tensile strength
Acoustic emission testing