Ultrasonic wall loss monitoring of rough surfaces

Mitigating the effects of surface morphology changes during ultrasonic wall thickness monitoring

“…In those ultrasonic signals there is a clear indication of distortion of the shape of the reflected wave pulse. The authors have in the past reported on this problem and also devised a more robust algorithm [6], adaptive cross correlation (AXC), that is more reliable at extracting wall thickness trends in the presence of surface morphology changes. In this paper, the basics of AXC and its performance will be recalled, following this further improvements in the capabilities to monitor corrosion rates ultrasonically by the combination of measurements from multiple sensors will be presented.…”

“…4 have highlighted that AXC can result in much better estimates of corrosion rates/wall thickness trends because it actively corrects for surface morphology induced distortions of the monitored ultrasonic signals. In order to assess how well different algorithms can extract corrosion rates from rough surfaces with evolving surface morphology, the performance of AXC and other standard time of flight extraction methods (peak to peak [P2P], first arrival [FA] and cross correlation [XC]) was simulated [6]. The performance simulation required several sub modules:…”