Acoustic emissions (AE) are used in structural applications to detect, locate, and characterize internal damage to equipment that is under pressure and in use. AE occur when a material undergoes irreversible changes in its internal structure and propagate to the surface where they are recorded by sensors. The information provided identifies crack formation and growth, melting, slip and dislocation movements, and phase transformations.
Because damage is cumulative, advanced forms of AE can be used to monitor structural health. Discerning between developing and stagnant defects provides an immediate indication relating to the strength or risk of failure of a component. This method is also used to detect and measure leaks, mechanical vibrations, and mechanical friction.