The Measurement of Regular and Irregular Surface Cracks Using the Alternating Current Potential Difference Technique / MP. Connolly
- Conference Author
- Special Applications and Advanced Techniques for Crack Size Determination (1993 : Atlanta, Georgia)
- Physical Description
- 1 online resource (14 pages) : illustrations, figures, tables
- Additional Creators
- Connolly, MP., American Society for Testing and Materials, and ASTM International
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- Machine generated contents note: The Measurement of Regular and Irregular Surface Cracks Using the Alternating Current Potential Difference Technique / M. P. Connolly -- Fatigue Crack Growth Measurements in TMF Testing of Titanium Alloys Using an ACPD Technique / Y. Dai / N. J. Marchand / M. Hongoh -- Measurement of Multiple-Site Cracking in Simulated Aircraft Panels Using AC Potential Drop / D. A. Jablonski -- The Influence of Crack Deflection and Bifurcation on DC Potential Drop Calibration / C. P. Tabrett / D. J. Smith / P. C. McKeighan -- Application of a Crack Length Measurement with a Laser Micrometer to R-Curve Tests / G. Millour / J.-M. Schwab / J. Delmotte / B. Journet / L. Legendre -- Improved Load Ratio Method for Predicting Crack Length / X. Chen / J. A. Joyce / W. Wright / P. Albrecht -- Ultrasonic Size Determination of Cracks with Large Closure Regions / O. Buck / R. B. Thompson / D. K. Rehbein -- Apparatus for Ultrasonic In Situ Accurate Crack Size Measurement on Laboratory Test Specimens / D. Francois / Y. Park / D. De Vadder -- Nondestructive Crack Size and Interfacial Degradation Evaluation in Metal Matrix Composites Using Ultrasonic Microscopy / D. Blatt / J. R. Jira / M. P. Blodgett / P. Karpur / T. E. Matikas.
- Summary
- The alternating current (AC) potential difference technique for measuring the growth of regular and irregular surface cracks is described. This technique is based on injecting high frequency alternating current into the metal specimen and measuring the change in voltage on the surface produced by the presence of a crack. The high frequency current tends to flow in a thin layer of the metal surface; therefore, low currents are required to produce measurable voltages on the specimen surface. Although AC techniques are increasingly employed for the measurement of surface cracks, one of the difficulties with the approach is the problem of interpreting the measured data in terms of crack shape and size. The objective of this paper is to present an inversion algorithm that can be used to determine the shape and size of surface cracks from measurements of the surfaces' voltage. This inversion algorithm is based on a model of the electromagnetic field problem, and the algorithm enables the voltage data obtained from measurements in the crack region to be interpreted directly in terms of the crack shape and size. Examples of the application of the inversion algorithm to the interpretation of voltage measurements obtained from a single semielliptical and two semielliptical intersecting surface cracks are described.
- Dates of Publication and/or Sequential Designation
- Volume 1995, Issue 1251 (January 1995)
- Subject(s)
- Other Subject(s)
- ISBN
- 0803120036
9780803120037
9780803153080 (e-ISBN) - Digital File Characteristics
- text file PDF
- Bibliography Note
- Includes bibliographical references 12.
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Full text article also available for purchase. - Reproduction Note
- Electronic reproduction. W. Conshohocken, Pa. : ASTM International, 1995. Mode of access: World Wide Web. System requirements: Web browser. Access may be restricted to users at subscribing institutions.
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- Mode of access: World Wide Web.
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- ASTM International PDF Purchase price USD25.
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