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Modeling of Ultrasonic Nondestructive Testing of Surface-breaking Cracks

Per-Åke Jansson (Institutionen för tillämpad mekanik, Dynamik) ; Anders Boström (Institutionen för tillämpad mekanik, Dynamik)
Proceedings 18th World Conference of Non-Destructive Testing, 16-20 April 2012, Durban, South Africa (2012)
[Konferensbidrag, refereegranskat]

A complete model of ultrasonic nondestructive testing of defects in thick-walled components has been developed since more than a decade and has resulted in the computer program UTDefect. The program includes models of transmitting ultrasonic probes, and through a reciprocity argument also recieving probes. A number of simply shaped defects are included. Here the focus is on surface-breaking strip-like cracks, and a comparison of these with strip-like interior cracks. Both scattering problems are solved with a hyper-singular integral equation method, where the unknown crack-opening displacement (COD) is expanded into sets of Chebyshev functions. These expansions are different for the two cracks; whereas the interior crack has a COD that behaves as a square root at the tips, the surface-breaking COD has a finite value at the crack mouth, and these behaviours must be taken into account. Numerical comparisons are made between the two cracks, and it seems that the interior crack pushed to the surface behaves very much like the surface-breaking one, except at very low frequencies (crack size less than half a wavelength). Favourable comparisons with experiments are also made.

Nyckelord: Ultrasonics, modeling, crack



Denna post skapades 2012-12-12. Senast ändrad 2015-03-30.
CPL Pubid: 167584

 

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Institutioner (Chalmers)

Institutionen för tillämpad mekanik, Dynamik

Ämnesområden

Fastkroppsmekanik

Chalmers infrastruktur