Acoustic Emission Detection and Characterisation Using Networked FBG Sensors

Acoustic Emission (AE) events are often generated when a material undergoes irreversible changes to its internal structure and thus provides a basis for the detection of damage in structural components. A method for AE localisation featuring a single laser source coupled to three optical fibre Bragg grating sensors is described and experimentally demonstrated on a thin aluminium panel. The localisation algorithm analyses the time domain waveform and the corresponding frequency spectrum to determine the time of arrival and velocity of an AE signal from which its epicentre is estimated using a grid search. Experimental results are shown to demonstrate the accuracy of the method.