New possibilities for weld assessment using inverse wavefield extrapolation

Abstract

New technological capabilities in both girth weld Non Destructive Testing (NDT) and girth weld material characterization open the door for new ways of weld assessment. The paper gives examples of new technologies currently being developed in NDT and investigates how these technologies could add value, in the field, on weld testing and assessment. The guiding principle in this investigation is that the data gathered in NDT should be sufficient for making an engineering decision. It will be argued that this is not currently the case as NDT is now used in a qualitative check on the welding process rather than a quantitative information source on the weld strength.An overview of technologies like Inverse Wave Extrapolation (IWEX), Full Matrix Capture (FMC), and Sampling Phased Array (SPA) will be given. These technologies show promise to increase the quality of data received from Automated Ultrasonic Testing (AUT) of pipeline girth weld. The most important improvement is that an image of the defect is generated, in three dimensions, which allows for improved assessment of the impact of detected flaws on the weld strength. The paper will then show how these new capabilities could be combined with new technology in material testing and finite element calculations, which has specific value for strain based pipeline designs. The result is a vision on the future of girth weld assessment.