Radiographic modelling for NDE of subsea pipelines
Autor: | Carsten Bellon, Peter Huthwaite, Stefan Hohendorf, Misty I. Haith, Michael J. S. Lowe, Uwe Zscherpel, Andreas Deresch, Uwe Ewert |
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Přispěvatelé: | Engineering & Physical Science Research Council (EPSRC), NDE Research Association Ltd |
Rok vydání: | 2017 |
Předmět: |
Subsea pipeline inspection
Technology Materials science Modelling validation Backscatter Image quality Acoustics media_common.quotation_subject Materials Science Materials Science Characterization & Testing 01 natural sciences 09 Engineering Collimated light 0103 physical sciences Contrast (vision) General Materials Science 010301 acoustics Image resolution Simulation Digital radiography media_common 010302 applied physics Science & Technology Mechanical Engineering Tangential radiography Detector Condensed Matter Physics Intensity (heat transfer) |
Zdroj: | NDT & E International. 86:113-122 |
ISSN: | 0963-8695 |
DOI: | 10.1016/j.ndteint.2016.11.006 |
Popis: | This work presents an investigation of the accuracy of a radiographic simulation model applied to subsea pipeline inspections. Experimental measurements of a sample in a water tank are used to develop a set of calibrated simulation parameters for the modelling software aRTist. Image quality parameters such as signal-to-noise ratio, contrast and basic spatial resolution are compared with the aim of matching simulated values to experimental results. With this method signal-to-noise ratio was successfully matched while differences were still found in contrast-to-noise ratio comparisons. This means that measurements depending on absolute intensity are not accurate enough, however wall thickness measurements in tangential images, which are not based on absolute intensity, were found to produce similar results in simulated and experimental cases. The differences in contrast and intensity are thought to be due to detector backscatter and additional scatter from out-of-setup objects within the exposure bay, due to a lack of source collimation. These would affect the experimental results but were not included in the simulated setup. This was investigated by including different proportions of peripheral water and other objects in the modelled setup and examining the effect on image quality parameters. Results show that this additional scatter has a significant impact on the radiograph, particularly on image contrast, and is therefore the likely cause of differences between experimental and simulated images. This implies that it will be very difficult to completely match simulated to experimental results, as including all possible scattering objects in the model would be very complex. An improvement could be made by using real subsea data to estimate this additional scattering, which could then be used to calibrate the model. However there would still be significant uncertainty in the ability of the model to accurately produce realistic intensity and contrast. |
Databáze: | OpenAIRE |
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