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Displacement pattern matching and boundary-element methods for elastic-plastic stress analysis

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Abstract

A two-dimensional hybrid experimental-numerical technique for elastic-plastic stress analysis is presented. This technique results from merging two relatively new technologies in engineering mechanics: boundary-element methods and image processing. A syntactic pattern recognition scheme, termed ‘displacement pattern matching’ (DPM), determines the displacement boundary conditions which are used in an elasticplastic boundary-element method (EPBEM) code. The result is an automated stress-analysis tool.

Displacement pattern matching is a process where displacements are measured by tracking an arbitrary array of ‘black’ spots on a ‘white’ specimen. The digitized images of the specimen are compared in a double-exposure format to determine displacements. Displacement pattern matching is a full-field technique, with spatial resolution on the order of. 1 pixels.

Displacement pattern matching supplies the actual specimen displacement increments to the EPBEM code which is based on a von Mises, isotropic work-hardening constitutive model. Given these displacements and free surface conditions, EPBEM is able to incrementally calculate the internal state of stress at selected locations. Results obtained for a variety of geometries and loading conditions compared well with ANSYS finite-element solutions and selected published experimental solutions and therefore are encouraging.

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Authors and Affiliations

  1. Department of Mechanical Engineering, University of Maryland, 20742, College Park, MD

    J. S. Sirkis (SEM Member) is Assistant Professor)

  2. Department of Aerospace Engineering, Mechanics and Engineering Sciences, University of Florida, 32611, Gainesville, FL

    C. E. Taylor (SEM Honorary Member) is Professor)

Authors
  1. J. S. Sirkis
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  2. C. E. Taylor
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Sirkis, J.S., Taylor, C.E. Displacement pattern matching and boundary-element methods for elastic-plastic stress analysis. Experimental Mechanics 30, 26–33 (1990). https://doi.org/10.1007/BF02322698

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  • DOI: https://doi.org/10.1007/BF02322698

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