This paper presents the reliability analysis of a manual ultrasonic time of flight diffraction test system for characterization of surface breaking inclined cracks. Probability of detection (POD) and probability of sizing (POS) curves for the detection and sizing of such cracks have been developed from experimental data. In the development of
POD and POS curves, it has been assumed and subsequently verified that the signal responses (â values for an angle of inclination of the crack q) have a normal distribution. The effects of probe angle and probe center spacing on both POD and POS have been investigated. The curves obtained in this work can be useful in risk based test planning for simple geometry components, such as pipelines and boiler headers, using a manual/automated time of flight diffraction system.
ASM International, ASM Metals Handbook, eighth edition, Vol. 17, Metals
Park, Ohio, ASM, 1976.
BSI British Standards, BS 7706: Guide to Calibration and Setting-up of the
Ultrasonic Time of Flight Diffraction (TOFD) Technique for the Detection,
Location and Sizing of Flaws, London, BSI British Standards, 1993.
Carvalho, A.A., J.M.A. Rebello, R.R. Silva and L.V.S. Sagrilo, “Reliability of
the Manual and Automatic Ultrasonic Technique in the Detection of Pipe
Weld Defects,” Insight, Vol. 48, 2006, pp. 649–654.
Charlesworth, J.P. and J.A.G. Temple, Engineering Applications of Ultrasonic
Time of Flight Diffraction, second edition, Hertfordshire, England, Research
Studies Press, 2001.
Deutsches Institut für Normung, ENV 583-6: Non-destructive Testing —
Ultrasonic Examination Part 6: Time of Flight Diffraction Technique as a
Method for Detection and Sizing of Discontinuities, European prestandard,
Berlin, Deutsches Institut für Normung, 2000.
Forsyth, David S., Abbas Fahr, Dirk V. Leemans and Ken I. McRae, “Development
of POD from In-Service NDI Data,” Review of Progress in Quantitative
Nondestructive Evaluation, Vol. 19B, D.O. Thompson and D.E.
Chimenti, eds., Melville, New York, AIP, 2000, pp. 2167–2174.
Ginzel, E., “Ermolov Sizing Equations Revisited,” NDT.net, Vol. 7, 2002.
Gupta, S.C. and V.K. Kapoor, Fundamental of Mathematical Statistics, ninth
edition, New Delhi, India, Sultan Chand & Sons, 1994.
Nath, S.K., K. Balasubramaniam, C.V. Krishnamurthy and B.H. Narayana,
“Sizing of Surface-Breaking Cracks in Complex Geometry Components by
Ultrasonic Time-of-Flight Diffraction (TOFD) Technique,” Insight, Vol.
49, 2007, pp. 200–206.
Nath, S.K., K. Balasubramaniam, C.V. Krishnamurthy and B.H. Narayana,
“An Ultrasonic Time of Flight Diffraction Technique for Characterization
of Surface-Breaking Inclined Cracks,” Materials Evaluation, Vol. 67, 2009,
pp. 141–148.
NIST/Sematech, Engineering Statistics Handbook, e-handbook of Statistical
Methods, available at www.itl.nist.gov/div898/handbook, 2003.
Ogilvy, J.A. and J.A.G. Temple, “Diffraction of Elastic Waves by Cracks:
Application to Time of Flight Inspection,” Ultrasonics, Vol. 7, 1983,
pp. 259–269.
Trimborn, N., “The Performance of the Time of Flight Diffraction
(TOFD) Technique in Various International Round Robin Trials and the
Continuing Research Work Underway,” NDT.net, Vol. 3, 1998.
Visser, W. (Pim), “POD/POS Curves for Non-destructive Examination,”
Offshore Technology Report 2000/018, Weybridge, England, Visser Consultancy,
2000.
Wall, M. and S. Burch, “Worth of Modeling for Assessing the Intrinsic
Capability of NDT,” 15th. WCNDT, Rome, 15–21 October 2000.
Wu, Y.-H., private communication, 2008.
Wu, Y.-H. and C.C. Hsiao, “Reliability Assessment of Automated
Eddy Current System for Turbine Blades,” Insight, Vol. 45, 2003,
pp. 332–336.