STP1411: Automated Deformation Mapping in Fatigue and Fracture

    Johnson, DA
    Materials Research Engineer, Materials and Manufacturing Directorate, Air Force Research Laboratory (AFRL/MLLMN), OH

    Pages: 13    Published: Jan 2002


    Abstract

    An example of the use of deformation mapping in the study of fatigue-crack growth (FCG) has been developed, and preliminary steps in automating this method have been made. The deformation-mapping technique used was based on the correlation of corresponding subsets of digital images acquired while the specimen was under varying loading conditions. The result was a full-field in-plane deformation map which showed, in general, nonlinear behavior under loading. The deformation map of the region near the crack tip was used in calculating both Mode-1 (opening) and Mode-2 (shearing) near-tip stress-intensity-factors. Also, measurements of crack opening displacements (CODs) and crack sliding displacements (CSDs) have been made for various measurement locations. In this way, the effect of measurement location upon closure measurements can be studied. Lastly, a Synthesis of Modeling and Application in Real-time (SMART) system has been proposed, and work on this system has been ongoing.

    Keywords:

    fatigue-crack growth, mixed mode, deformation mapping, image analysis, closure, crack opening displacement, crack sliding displacement


    Paper ID: STP10613S

    Committee/Subcommittee: E08.93

    DOI: 10.1520/STP10613S


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