Guided wave inspection has the advantage of providing full volumetric coverage of tens of metres of pipe from a single test location. However, guided wave behaviour is complex. There are many factors to consider such as the numerous possible vibrational modes, dispersion and multiple reflections. The guided wave inspection technique is potentially immensely valuable for unpiggable sections of pipeline such as at cased road crossings. However, in situations such as this, there are often bends in the pipe. The presence of the bend is known to distort the received signals, particularly in tight bends. Finite element modelling has been used to understand the behaviour of torsional family guided waves in pipe bends for a tight bend radius in a 3" Schedule 40 steel pipe (88.9 mm outer diameter, 5.49 mm wall thickness). The orientation and amplitudes of the wave modes received after the bend were quantified for a range of possible input excitation scenarios. In most cases, both torsional and flexural wave modes were excited beyond the bend to some degree. This indicates that standard guided wave inspection would be inaccurate for inspection beyond pipe bends and there would be greater potential for false calls. Moreover, the models were used to examine the effect of the bend on reflected signals from a flaw. It was found that the amplitudes of the reflections were significantly affected. This would have implications for flaw characterisation techniques based on signal amplitude.
Inspection of pipe networks containing bends using long range guided waves
2012
9 Seiten, 7 Bilder, 8 Quellen
Aufsatz (Konferenz)
Datenträger
Englisch
Long range inspection of rail using guided waves
Tema Archiv | 2002
|Long range inspection of rail using guided waves. Field experience
Tema Archiv | 2003
|Long range inspection of rail using guided waves-field experience
Tema Archiv | 2004
|EMAT pipe inspection with guided waves
Tema Archiv | 2012
|Rapid Long range Inspection of Chemical Plant Pipework Using Guided Waves
British Library Conference Proceedings | 2000
|