Session: 15-01: Structural Health Monitoring

Paper Number: 100343

100343 - The Use of Circumferential Guided Waves to Monitor Axial Cracks in Pipes 

The detection of axial cracking in pipe junctions that contain the mixing of high and low-temperature fluids is a significant structural health monitoring challenge. This study presents a novel monitoring system for axial cracks in piping utilising circumferential guided waves which allows rapid inspection and significant volumetric coverage from a single transducer position. Specifically, this initial study assesses the performance of the circumferential SH0 mode system at frequencies below the cut-off of higher-order modes in a plain pipe. The use of multiple transits of the SH0 wave was examined with improvements to sensitivity identified due to the additive quality of defect reflections on successive revolutions. Two defect detection methods were investigated: the RMS of the residuals produced using baseline subtraction and the percentage change of the ratio of the first and third arrivals of the SH0 wave. The significant axial beam spread of the SH0 wave allowed axially offset defects to be detected and the performance of the system has been quantified for a range of industrially relevant defect sizes at different distances away from the transmitter. The experimental validation showed the system to be stable over the monitoring period with promising sensitivity to axial cracking for a variety of industrial applications.

Presenting Author: Euan Rodgers Imperial College London