Acoustic Emission and Durability of Composite Materials

Nathalie Godin has been a senior lecturer at the National Institute of Applied Sciences (INSA, in MATEIS laboratory) in Lyon, France since 1996. She has more than 20 years of experience in the field of acoustic emission and the study of mechanisms of damage of composite materials.Pascal Reynaud has been a Research Fellow at the CNRS (INSA, in the MATEIS laboratory) in France since 1992. His research activities mainly concern the behavior and damage of ceramic matrix composites.Gilbert Fantozzi has been Professor Emeritus at the National Institute of Applied Sciences (INSA, in the MATEIS laboratory) of Lyon, France since 2007. He is a specialist in the field of the elaboration of ceramic materials, the thermomechanical behavior of ceramics and the microstructure–properties relationships of ceramics.

• Introduction ixChapter 1 Acoustic Emission: Definition and Overview 11.1 Overview 11.2 Acoustic waves 81.2.1 Infinite medium: volume waves 81.2.2 Semi-infinite medium: surface waves 91.2.3 Guided waves 91.2.4 Anisotropic medium and wave attenuation 101.3 The sensors and acquisition system 121.4 Location of sources 161.5 The extracted descriptors from the AE signal 211.5.1 Time domain descriptors 221.5.2 Frequency domain descriptors 261.5.3 Time–frequency analysis 301.6 The different analyses of AE data 321.6.1 Conventional analysis: qualitative analysis 321.6.2 Multivariable statistical analysis: application of pattern recognition techniques 421.7 Added value of quantitative acoustic emission 55Chapter 2 Identification of the Acoustic Signature of Damage Mechanisms 592.1 Selection of signals for analysis 592.2 Acoustic signature of fiber rupture: model materials 632.2.1 Characterization of the fiber at the scale of the bundle 642.2.2 At the microcomposite scale 692.2.3 At the minicomposite scale 722.3 Discrimination using temporal descriptors of damage mechanisms in composites: single-descriptor analysis 752.4 Identification of the acoustic signature of composite damage mechanisms from a frequency descriptor 792.5 Identification of the acoustic signature of composite damage mechanisms using a time/frequency analysis 812.6 Modal acoustic emission 822.7 Unsupervised multivariable statistical analysis 842.7.1 Damage identification for organic matrix composites 852.7.2 Static fatigue damage sequence identification for a ceramic matrix composite 892.7.3 Identification of the cyclic fatigue damage sequence for a ceramic matrix composite 922.7.4 Validation of cluster labeling 962.8 Supervised multivariable statistical analysis 1002.8.1 Library created from data based on model materials 1002.8.2 Library created from structured data by unsupervised classification 1032.9 The limits of multivariable statistical analysis based on pattern recognition techniques 1042.9.1 Performance of algorithms 1052.9.2 Influence of the acquisition conditions and the geometry of the samples 1132.10 Contribution of modeling: towards quantitative acoustic emission 120Chapter 3 Lifetime Estimation 1233.1 Prognostic models: physical or data-oriented models 1253.2 Generalities on power laws: link with seismology 1283.3 Acoustic energy 1333.3.1 Definition of acoustic energy 1333.3.2 Taking into account coupling and definition of equivalent energy 1343.4 Identification of critical times or characteristic times in long-term tests: towards lifetime prediction 1363.4.1 The R AE emission coefficient 1373.4.2 Optimal circle contribution: highlighting the critical region 1393.4.3 The attenuation coefficient B 1403.4.4 The R LU coefficient for cyclic fatigue tests 1423.4.5 The coupling between acoustic energy and mechanical energy: the Sentry function 1443.5 Simulation of the release of energy using a power law: prediction of the rupture time 146Conclusion 151Bibliography 153Index 181