Understanding Acoustic Emission Testing- Reading 1 Part B-A

Types of AET
Acoustic emissions are broadly classified into two major types namely;
• continuous type (associated with lattice dislocation)
• burst type. (twinning, micro yielding, development of crack)
The waveform of continuous type AE signal is similar to Gaussian random
noise, but the amplitude varies with acoustic emission activity. In metals and
alloys, this form of emission is considered to be associated with the motion of
dislocations. Burst type emissions are short duration pulses and are
associated with discrete release of high amplitude strain energy. In metals,
the burst type emissions are generated by twinning, micro yielding,
development of cracks.
• Continuos type (Gaussian random noise) → Motion of dislocation,
• Burst type (discrete high amplitude strain energy) → twinning, micro
yielding, development of cracks
Charlie Chong/ Fion Zhang
http://www.geocities.ws/raobpc/AET.html