What does acoustic emission testing (AET) primarily detect?

Acoustic emission testing (AET) primarily detects sound waves generated by the rapid release of energy from localized sources within materials. This phenomenon occurs during events such as crack formation, plastic deformation, or other structural changes, where stress induces elastic waves that propagate through the material.

AET is particularly valuable because it provides real-time monitoring of structural integrity, allowing for early detection of defects that can lead to failure. By analyzing the characteristics of the emitted sound waves—such as their frequency, amplitude, and duration—inspectors can infer the type, location, and severity of the underlying issues within a material or structure.

Other methods mentioned, such as vibrational patterns, thermal variations, or electrical conductivity changes, do not specifically relate to the detection of stress-induced sound waves and are used in different forms of nondestructive testing. Thus, recognizing that AET focuses on these sound waves distinguishes its unique application in assessing material condition and integrity.