The U of M Acoustic Emission Project

What are AEs? Why AEs for fault monitoring?

Automatic fault monitoring techniques are being considered as a means to safely simplify or dispense off with expensive periodic inspection and preventive maintenance procedures. One such automatic monitoring technique is based on the detection of Acoustic Emissions in the material.

An early indicator of the onset of material failure due to fatigue and/or stress is the appearance of microcracks. Generation of these cracks create ultrasonic waves that propagate in the material. These waves are called Acoustic Emissions (AEs).

Detection of these AEs, hence, provide a reliable method for predicting material failure. However, in practice, these AE signals are buried in strong interference, caused due to the mechanical motion in the machine. In consequence, detection of these AEs should be accomplished at very low SNRs, with very minimal a priori knowledge of the signal and/or noise characteristics.

The block diagram below shows the proposed hierarchy of the system to be used for automatic fault monitoring.

The contribution of the Signal Processing Group to this project will be in the following areas :

Prefiltering and Noise cancellation
Detection of the AE signal
Localization of the fault
Classification of the fault