acoustic emission

plural acoustic emissions

1. uncountableacousticsengineeringA phenomenon wherein external stimuli such as mechanical loading generate physical vibrations.
2. countableengineeringA physical vibration caused by sudden movement within a material subjected to physical stress, often symptomatic of a defect.

   Acoustic emissions are only generated when some abrupt and permanent change takes place somewhere in the material.

   1990, Adrian A. Pollock, “Acoustic Emission Inspection”, in ASM Handbook, 17th edition, →ISBN, page 287