The number of applications to which the Acoustic Emission (AE) technique has been successfully applied is vast.
Examples include detecting and locating faults in pressure vessels, damage assessment in fibre-reinforced polymer-matrix composites, monitoring welding applications and corrosion processes, various process monitoring applications, global or local long-term monitoring of civil-engineering structures (e.g., bridges, pipelines, offshore platforms, etc.) and fault detection in rotating elements and reciprocating machines, to name but a few.
The scientific application of AE first emerged in the 1950's, but the decline of heavy industry, nuclear power and defence spending in the 1980s, together with some poor publicity, resulted in a quiet period for AE research. Nevertheless the technique has developed significantly and emerged as a very powerful method for numerous measurement problems, far beyond conventional non-destructive testing.
Today there is a transition to waveform-based analysis, which has opened up a new approach to AE analysis. Recent successes have been largely due to advances in high-speed digital waveform based AE instrumentation, improvements in high fidelity, high sensitivity broadband sensors and advanced PC-based signal analysis. This has given researchers an enhanced understanding of AE signal propagation, enabling a departure from traditional reliance on statistical analysis, significantly improving the monitoring capabilities of AE.
New developments have raised new problems, not least of which is sensor technology. Resonant transducers are useful in many applications but increasingly are replaced by sensors with broader frequency characteristics. Issues of flat response, sensitivity and calibration need to be addressed. Modern data transfer methods such as network techniques and wireless communication ensure that AE technology will be a field of interesting future developments and applications.