Originally published at The Sixth Japan-US NDT Symposium Emerging NDE Capabilities for a Safer World, on July 8, 2018
in industry has a vital role in assuring integrity of assets and safety for people and environment. A problem of concern is reducing incidents from crack-like flaws, in particular the difficulty in sizing and discriminating anomalies in the pipe and differentiating between critical defects near failure and benign manufacturing flaws which will remain stable though-out the life of pipeline.
The new Full Matrix Capture
(FMC) family of UT
imaging measurements is showing great potential and is considered the natural evolution of PA since it allows for characterization of flaws with any orientation.
Among FMC techniques, IWEX
uses two array probes and acquires up to 13 simultaneous modes, and it has been applied to girth welds, ERW, FW and FSW samples. With this paper we describe the IWEX technique and share the results and benefits of using it over Phased Array (PA)
such as straightforward interpretation and automation of the identification and sizing process which will reduce the dependence on human interpretation of inspection results.
The ideal NDE process should be carried out using a fully automated system: the planning, execution, evaluation and reporting would be all tasks performed by automated technologies and artificial intelligence that don’t need human intervention, thus taking the Human Factor out of the equation. Not yet reaching this level of automation, it is still possible to improve the overall quality of the NDE process to increase both speed and quality, while maintaining safety.
Ultrasonic Testing (UT) NDE is considered a safe, portable and reliable inspection method. Detection and characterization though depend upon factors like technician’s experience and skills, especially for shear wave UT
where an amplitude vs time signal (A-Scan) is the only given information from the specimen to be examined. With this technique there is very little data saved as a digital record as only screenshots can be saved. Advanced sizing is based on using maximum amplitude method for multi-faceted flaws, and tip diffraction method for smooth reflectors.
The evolution of shear UT was represented by the use of an array probe with the Phased Array (PA) technique from the medical industry: the new capabilities of simultaneously steering of the beam in multiple directions and assembly all the A-Scans in images, has made it easier to interpret any anomalies found during inspection. However, skill and experience are still very important factors to avoid false positive and false negative results (for example focusing distance from the array probe and false signals from mode conversion may lead to the wrong conclusions).
With FMC techniques, in particular with the Inverse Wave field Extrapolation method (IWEX), it is possible to image the results in a way that resemble the actual configuration of the flaw with improved information about the orientation of the anomaly and fewer false signals.