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Classification of stress-intensity factors from isochromatic-fringe patterns

Isochromatic fringes corresponding to different combinations of K I , K II and σ ox have been constructed, and the unique characteristics of the isochromatics can be used to classify the state of stress (K I , K II and σ ox ) at the crack tip

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Abstract

The stresses in the local neighborhood of a crack tip have been used to develop a relation between the isochromatic-fringe orderN, its position parametersr and θ and the stress field expressed in terms of stress intensities,K I ,K II , and a far-field stress σ ox . This relation was programmed and a plotting routine was developed to map isochromatic (σ1 − σ2) fields in the neighborhood of the crack tip.

The stress intensitiesK I andK II and the far-field stress σ ox were varied and isochromatic fields were constructed for each combination. As bothK II and σ ox influence the size, shape and orientation of the isochromatics loops in a systematic manner, the pictorial representation of the isochromatic fields can be used to classify the state of stress (K I ,K II and σ ox ) at the crack tip. Isochromatics which classify six different states of stress have been illustrated and methods used to determineK I ,K II , andσ ox in five of the six states are given.

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Authors and Affiliations

  1. University of Maryland, 20742, College Park, MD

    J. W. Dally (Professor of Mechanical Engineering)

  2. Structural Reliability Section, Ocean Technology Division, Noval Research Laboratory, 20375, Washington, DC

    R. J. Sanford (Head)

Authors
  1. J. W. Dally
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  2. R. J. Sanford
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Dally, J.W., Sanford, R.J. Classification of stress-intensity factors from isochromatic-fringe patterns. Experimental Mechanics 18, 441–448 (1978). https://doi.org/10.1007/BF02324279

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  • DOI: https://doi.org/10.1007/BF02324279

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