Vibration and Acoustic Emission Monitoring of a Girth Weld during a Resonance Fatigue Test

Abstract

This research is focused on LEVEL 1 detection and LEVEL 2 localization of damage which could be used as part of a structural health monitoring strategy. An experimental trial of acoustic emission and vibration monitoring techniques was carried out to monitor fatigue damage during a full scale resonance fatigue test on a girth welded pipe. The welded steel pipe was excited into the first mode of vibration using the resonance fatigue testing technique in order to determine the high cycle fatigue strength of the weld. The test applies a cyclic bending stress around the full pipe circumference at around 30Hz. The test was monitored in real time using acoustic emission and vibration monitoring. The damage sensitive features of the output from the vibra-tion data were compared with the acoustic emission parameters. This paper shows that combin-ing the vibration monitoring and acoustic emission results was effective since both techniques could detect damage from fatigue cracking in the extreme test conditions.