Internal ultrasonic examination of ring stiffened tubular joints
- TWI, Cambridge (United Kingdom). Structural integrity Dept.
- Culham Lab., Abingdon (United Kingdom). Marine Technology Support Unit
- Health and Safety Executive, Bootle (United Kingdom). Offshore Safety Div.
A study was carried out to determine fatigue crack initiation sites and crack growth rates in offshore tubular joints containing internal ring stiffeners. The occurrence of both externally and internally initiated cracking indicated that inspection requirements may need to include an additional examination of potential internal crack sites, which would not be detectable by external surface inspection methods. The objectives of this work were to develop ultrasonic test (UT) procedures for detecting radial cracks initiating in ring stiffeners, and to determine the detection performance of conventional UT for cracks initiating at both stiffener/chord and brace/chord welds. An angled longitudinal wave technique was highly successful in detecting stiffener ring inner edge cracking, down to 5mm deep. Sizing of cracks was problematic owing to the long beam paths and specimen curvature. If internal cracking of the stiffener rings is expected, the angled longitudinal wave technique could be applied to determine whether or not cracking from the ring inner edge exists.
- OSTI ID:
- 403641
- Report Number(s):
- CONF-9606279--; ISBN 0-7918-1492-0
- Country of Publication:
- United States
- Language:
- English
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