Damage Assessment Using Acoustic Emission

Acoustic Emission is widely used in the oil and petrochemical industry on storage tanks, pressure vessels, and pipelines, Its unique capabilities are now being increasing utilized in the assessment of civil structures. All highway bridges in the UK are assessed at 2 yearly intervals, which comprises of a visual survey often carried out from ground looking up at the structure. At 6 yearly intervals, the structure is closely examined visually and the engineer has the option to carry out nondestructive testing if there is suspicion of a defect. These inspections are crucial; a small defect missed in one assessment due to its size or obscured location may grow at an increased rate proportional to its size. By the time the defect has been identified, it may have already compromised the integrity of the structure and involve costly remedial works. Acoustic Emission (AE) can be used in two broad strategies: (1) global monitoring to assess large areas and (2) local monitoring for known or suspected defects. This paper reviews the uses of these two strategies, illustrating results of an extensive laboratory testing program and two case studies of these AE strategies. (Author)