Phased Array ultrasonics was chosen as the inspection method to detect first-layer, faying surface fatigue cracks around fastener holes beneath the fastener heads, without removal of the fastener. A novel inspection technique for rapidly and reliably inspecting the area around fastener holes for cracks and corrosion has been developed with no moving parts. The Phased Array design consists of a three-dimensional matrix of 504 ultrasonic elements on a cone that encircles the fastener head. Full circumferential scans are performed by programming the phased array focal laws to scan 360 deg of the fastener holes, using a combination of the following scan patterns: pulse-echo at 45 deg incident on the crack, pulse-echo at 90 deg, plus local scanning. This capability allows flexible coverage of the fastener hole and surrounding area, again with no moving parts. Additionally, the beam deflection capability means that one probe is adaptable to a wide range of fastener diameters and skin thickness. Numerical modeling along with experimental results was used to determine the optimal values for inner and outer radii of the cone, angle of the cone, number of elements and arrangement of the elements. Two complete prototype conical arrays were subsequently built. The final portion of this project included developing the specific inspection procedures, and undertaking the Probability of Detection study (POD) developed by the FAAs Airworthiness Assurance Nondestructive Tested Validation Center at Sandia National Laboratory. Special probes using conical array of ultrasonic crystals have been designed for the aircraft fastener inspections. A prototype probe with 504 elements was built, and integrated into a 64/512 Focus system. Further capability is currently being developed. This additional capability includes corrosion mapping, pitch-catch inspections, skin thickness measurements, detection of other defects such as exfoliation and shaft cracking. The final portion of this project includes developing specific inspection procedures and performing Probability of Detection (POD) tests to verify the capabilities.


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    Titel :

    FastfocusTM phased array system for air plane fastener inspections


    Weitere Titelangaben:

    Fastfokus<sup>TM</sup> Gruppenstrahlersystem zur Untersuchung von Flugzeug-Verbindungselementen


    Beteiligte:
    Moles, M. (Autor:in) / Dupuis, O. (Autor:in) / Lamarre, A. (Autor:in) / Herzog, P. (Autor:in) / Ashbaugh, M. (Autor:in) / Selman, J. (Autor:in)


    Erscheinungsdatum :

    2004


    Format / Umfang :

    8 Seiten, 12 Bilder, 3 Quellen


    Anmerkungen:

    (Nicht paginiert)


    Medientyp :

    Aufsatz (Konferenz)


    Format :

    Datenträger


    Sprache :

    Englisch





    Inspection of Fastener Holes Using Phased Array Ultrasonic Fast Focus

    Herzog, P. G. / Selman, J. J. / Moles, M. et al. | British Library Conference Proceedings | 2004


    Pipeline girth weld inspections using ultrasonic phased arrays

    Moles, M. / Dube, N. / Labbe, S. et al. | Tema Archiv | 2004


    Ultrasonic phased arrays for pipeline girth weld inspections

    Moles, M. / Dube, N. / Russell, M. | Tema Archiv | 2000


    Pipeline girth weld inspections using ultrasonic phased arrays

    Moles, Michael / Dube, Noel / Ginzel, Ed | Tema Archiv | 2003