Volume 2, Issue 3 (March 2005)

    Characterization of Crack Length Measurement Methods for Flat Fracture with Tunneling

    (Received 12 November 2003; accepted 11 March 2004)

    Published Online: 2005

    CODEN: JAIOAD

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    Abstract

    This paper compares area-average and unloading compliance crack-growth values with experimental crack-front shapes recorded at various stages of crack growth during fracture tests conducted on 2024-T351 aluminum alloy plate. Crack-front shapes were determined by fracturing the specimen up to a predetermined amount of crack growth and fatigue cycling the specimen for about 4000 cycles at a high stress ratio to mark the crack-front location. For each shape, the area-average and unloading compliance crack lengths were determined. Boundary collocation results provide an approximation to the δ5 unloading compliance crack length. The crack tunneling results show that the area-average technique produces crack-length measurements more representative of the straight-front finite element analyses than optical based surface measurements. The δ5 technique is significantly more sensitive to tunneling than the CMOD technique and is easier to apply than the area-average technique.


    Author Information:

    James, MA
    Staff Scientist, National Institute of Aerospace, Hampton, VA

    Newman, JC
    Professor, Mississippi State University, Mississippi State, MS


    Stock #: JAI12053

    ISSN: 1546-962X

    DOI: 10.1520/JAI12053

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    Author
    Title Characterization of Crack Length Measurement Methods for Flat Fracture with Tunneling
    Symposium Fatigue and Fracture Mechanics: 34th Volume, 2003-11-21
    Committee E08