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    In Vivo Strain Estimates for Medical Implants

    Published: 2013

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    Anticipating the in vivo loading conditions is a challenging aspect of validating the design and durability of cardiovascular implants. Complex implant geometries, multi-axial displacements, device/tissue interactions, and time-dependent factors can make it difficult or impossible to identify a single loading cycle that is representative of the full range of conditions. Computational modeling is often used to reduce a large number of complex conditions into representative alternating and mean strains at locations of maximum strain. A novel approach for estimating the alternating and mean strains during in vivo loading will be presented. The method determines local strains by deforming a finite-element model of an implant into a three-dimensional geometry reconstructed from two-dimensional images of a physically deformed implant. The method is then extended to in vitro fatigue experiments. Two examples are given of a structural heart implant.


    computational models, experimental mechanics, inverse methods, medical devices, imaging, nitinol

    Author Information:

    Perry, Kenneth E.
    ECHOBIO LLC, Bainbridge Island, WA

    Quest, Matthew M.
    Cardiac Dimensions, Inc., Kirkland, WA

    Johnson, Tim J.
    Cardiac Dimensions, Inc., Kirkland, WA

    Conta, Robert
    Cardiac Dimensions, Inc., Kirkland, WA

    Committee/Subcommittee: E08.05

    DOI: 10.1520/STP155920130028