DETERMINATION OF ACOUSTIC EMISSION SOURCES ENERGY AND APPLICATION TOWARDS LIFETIME PREDICTION OF CERAMIC MATRIX COMPOSITES

摘要

Ceramic Matrix Composites (CMCs) are anticipated for use in aeronautical engines. Expected lifetimes in service conditions that are of thousands of hours are unattainable during laboratory tests. The objective of this paper is to propose an Acoustic Emission (AE) based approach to lifetime prediction for CMCs. The energy of AE sources is extracted from the energy recorded during tests, with a view to obtain a proper measure of stress-induced damage during static fatigue at high temperature on woven SiCf/[Si-B-C] composites. The use of two AE sensors allows the evaluation of energy attenuation due to propagation distance, acquisition system and damage accumulation. The analysis of AE sources energy release in static fatigue reveals a critical evolution of local energy release in the vicinity of rupture location at 50% of rupture time. This criticality is assessed using the Benioff law and it is attributed to subcritical crack growth in fibers.