Acoustic emission non-destructive testing of structures using source location techniques.

Abstract

The technology of acoustic emission (AE) testing has been advanced and used at Sandia for the past 40 years. AE has been used on structures including pressure vessels, fire bottles, wind turbines, gas wells, nuclear weapons, and solar collectors. This monograph begins with background topics in acoustics and instrumentation and then focuses on current acoustic emission technology. It covers the overall design and system setups for a test, with a wind turbine blade as the object. Test analysis is discussed with an emphasis on source location. Three test examples are presented, two on experimental wind turbine blades and one on aircraft fire extinguisher bottles. Finally, the code for a FORTRAN source location program is given as an example of a working analysis program. Throughout the document, the stress is on actual testing of real structures, not on laboratory experiments.

Characterisation of the damaging micromechanisms in a pearlitic ductile cast iron and damage assessment by acoustic emission testing

“…The software AEwin was used to process, visualise, and store the AEs in real time. The sensors were coupled/bonded to the fixed parts of the tensile machine by means of a thin layer of silicon (Loctite 595) . Figure shows the AE system layout and testing set‐up.…”

“…The reliability of the sensor coupling was checked by pencil lead break (PLB) test prior to the main tests . The AE amplitude threshold was set equal to 45 dB; the peak definition time (PDT), the hit definition time (HDT), and the hit lockout time (HLT) were set equal to 200, 800, and 1000 microseconds, respectively . A 50‐kHz high‐pass filter was applied as suggested in the literature, even though the sensors are mainly operating within 100 ÷ 450 kHz.…”

“…The sensors were coupled/bonded to the fixed parts of the tensile machine by means of a thin layer of silicon (Loctite 595). 18,21 Figure 5 shows the AE system layout and testing set-up. Sensor 1 was the closest to the specimen to detect the genuine signals due to the specimen damage process even though the sensor was not directly located on the specimen.…”

“…The AEs can be analysed in real time, and they can be post processed in order to characterise the state of health of the monitored systems. Several studies provide approaches/methods to analyse the AE data for the damage assessment of structures . AE testing has been increasingly applied in automated monitoring processes, especially for infrastructural systems .…”

“…Several studies provide approaches/methods to analyse the AE data for the damage assessment of structures. [17][18][19][20][21] AE testing has been increasingly applied in automated monitoring processes, especially for infrastructural systems. 13,[22][23][24] A schematic application of the technique is shown in Figure 2A (by Mistras LTD).…”