You are being redirected because this document is part of your ASTM Compass® subscription.
    This document is part of your ASTM Compass® subscription.

    If you are an ASTM Compass Subscriber and this document is part of your subscription, you can access it for free at ASTM Compass

    Three-Dimensional CTOA and Constraint Effects During Stable Tearing in a Thin-Sheet Material

    Published: 01 January 1995

      Format Pages Price  
    PDF (364K) 20 $25   ADD TO CART
    Complete Source PDF (17M) 834 $109   ADD TO CART

    Cite this document

    X Add email address send
      .RIS For RefWorks, EndNote, ProCite, Reference Manager, Zoteo, and many others.   .DOCX For Microsoft Word


    A small strain theory, three-dimensional elastic-plastic finite element analysis was used to simulate fracture in thin sheet 2024-T3 aluminum alloy in the T-L orientation. Both straight and tunneled cracks were modeled. The tunneled crack front shapes as a function of applied stress were obtained from the fracture surface of tested specimens. The stable crack growth behavior was measured at the specimen surface as a function of applied stress. The fracture simulation modeled the crack tunneling and extension as a function of applied stress. The results indicated that the global constraint factor, αg, initially dropped during stable crack growth. After peak applied stress was achieved, αg began to increase slightly. The effect of crack front shape on αg was small, but the crack front shape did greatly influence the local constraint and through-thickness crack-tip opening angle (CTOA) behavior. The surface values of CTOA for the tunneled crack front model agreed well with experimental measurements, showing the same initial decrease from high values during the initial 3mm of crack growth at the specimen's surface. At the same time, the interior CTOA values increased from low angles. After the initial stable tearing region, the CTOA was constant through the thickness. The three-dimensional analysis appears to confirm the potential of CTOA as a two-dimensional fracture criterion.


    Fracture, constraint, stable crack growth, CTOA, crack tunneling, thin sheet, elastic-plastic, finite-element, experimental data

    Author Information:

    Dawicke, DS
    Senior Scientist, Analytical Services and Materials, Inc., Hampton, VA

    Newman, JC
    Senior Scientist, NASA Langley Research Center, Hampton, VA

    Bigelow, CA
    Senior Scientist, FAA Technical Center, Atlantic City, NJ

    Committee/Subcommittee: E08.08

    DOI: 10.1520/STP16386S