ACOUSTIC-EMISSION SOURCE LOCATION USING LAMB WAVE MODES

This paper describes the development of a technique based on acoustic emission (AE) technology that can be used for global nondestructive ev aluation (NDE) of steel structures. This will also be useful for the s ubsequent. local inspection used to further monitor cracking, defectiv e connections, retrofit measures, and so forth. The dispersive nature of Lamb wave propagation in plates makes it possible to perform a line ar source location of AE events based on the arrival of different freq uency components (Lamb wave modes) of an AE event at a single transduc er. Experiments on steel beams and plates in the laboratory explored t he theory of wave propagation and digital signal processing needed to pursue this objective. Subsequent field investigation on a real bridge substantiated the applicability of this technique. This new technique could allow AE inspection to locate structural problems better, and w ith a reduced number of transducers.