Listening to the sound of materials: Acoustic emission for the analysis of material behaviour

Abstract

Applying a mechanical load to a composite material can result in many types of damage: debonding between the reinforcement and the matrix material, matrix cracking, failure of the reinforcement and delamination in the case of layered composites. To create a better understanding of the initiation, growth and interaction of the different types of damage, damage monitoring during mechanical loading is very important. Acoustic emission is the only nondestructive test technique capable of detecting all of the above mentioned damage types in composites. The possibilities of this technique to detect certain types of damage can only be proven by using other complementary techniques (replica technique, radiography, ultrasonics, optical and scanning electron microscopy). The research work on damage detection with the acoustic emission technique for different types of composite materials carried out at the Department of Metallurgy and Materials Engineering is presented.