ABSTRACT

Acoustic emission (AE) is extensively applied to nondestructive evaluation of materials and structures. In the most AE measurements, AE parameters are investigated to elucidate fracturing behaviors of materials.

Recently, based on elasto-dynamics, AE waveforms are studied theoretically. It is clarified that the waveforms could be synthesized as elastic waves due to crack formation (dislocation motion), and crack kinematics is mathematically given by the moment tensor. It is found that the eigenvalue analysis of the moment tensor is available for classifying crack types and determining crack orientations.

These theoretical treatment of AE waveforms is summarized and discussed.