Diffraction of SH wave by a semi-infinite round-tipped notch
- Datatrends Research, Mississauga, Ontario (Canada)
- AECL Research Chalk River Lab., Ontario (Canada)
This study is motivated by the need to characterize, from ultrasonic signals, the sharpness of a crack in pressure tubes of CANDU reactors. The crack is modelled by a semi-infinite notch with a finite width and root radius. The diffraction of plane SH wave is considered using the boundary integral equation (BIE) method. The surface of the notch is discretized by finite and semi-infinite boundary elements. An accurate and efficient quadrature method is applied to deal with the oscillations, irregularities, infinite extent and singularities of the integrals involved in the BIE. As a result, we were able to perform the computation on a 486-DX2-66 at a rate of 15 minute per frequency, for a 515 node mesh which supports sufficient accuracy for engineering applications. Numerical results for normalized frequency up to 4 are obtained. Justification of the results were carried out through comparison with the diffraction by a circular cavity and semi-infinite sharp crack. The most notable feature in the amplitude spectrum of the diffracted displacement for the current model is a combination of two types of oscillation periods. The short period is inversely proportional to the distance from the root of the notch to the field point, resembling the effect of the notch root as a point source. The long period appears to be inversely proportional to the half width, i.e. the root radius of the notch. Despite the simplicity of the model, the above findings enable a reasonable interpretation of measured data covering samples with artificially made rectangular and round-tipped notches, and fatigue cracks.
- OSTI ID:
- 175354
- Report Number(s):
- CONF-950686-; TRN: 95:006111-0316
- Resource Relation:
- Conference: Joint applied mechanics and materials summer meeting, Los Angeles, CA (United States), 28-30 Jun 1995; Other Information: PBD: 1995; Related Information: Is Part Of AMD - MD `95: Summer conference; PB: 520 p.
- Country of Publication:
- United States
- Language:
- English
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