Solution
AE testing was performed on a production steel casing from a geothermal field site in Cornwall and on a pipe covered with concrete. GW was deployed on the same concrete pipe with the aim of comparing the two methods. Finite Element Analysis was performed for a typical production steel casing in order to examine the ability of guided waves to travel along different layers of steel and concrete. VA was carried out on the same production steel casing using a hammer to simulate a crack.
The results have shown that for AE, the attenuation rate is very promising in terms of the possibility of identifying the crack while it is being developed.
GW deployed on the concrete pipe unveiled a higher attenuation rate but still acceptable for the purpose of this application. Finally, for VA performed on the production steel casing, a much higher attenuation rate was obtained compared with AE and GW, particularly for higher amplitude stimuli.