Modal Acoustic Emission

The operating principles of Modal Acoustic Emission (MAE) are summarized by placing transducers on the surface of a structure under test, applying stress to the structure and recording any ultrasonic stress waves which propagate out of the epicenter of the rapid release of strain energy caused by material fracture.

The transducers and hardware used in MAE testing are differentiated from the hardware used in traditional AE testing by considerably higher bandwidth, high fidelity transducers, and digital recording of waveforms; each of these differentiating aspects has enabled advances in the inspection of structures.

Relative to assessing fiber reinforced composite materials, the broad bandwidth performance of MAE hardware enables the discrimination of damage mechanisms from the highly heterogeneous microstructure of the material.

Due to the stress state which exists in closed end composite pressure vessels (i.e., bi-axial tension) coupled with the fact that the reinforcing fiber in the microstructure is the load bearing component of the material, the ability of MAE to focus on the detection and quantification of fiber tow fracture is critical to the success of the inspection.