STP1323

    A Comparison of Macroscopic to Microstructural Strain Fields in Cortical Bone

    Published: Jan 2001


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    Abstract

    This study describes a technique based on digitally comparing two images of a material taken at different stress or deformation levels (called machine vision photogrammetry) used to measure the microstructural strain fields in cortical bone. The technique allows the measurement of material surface displacements and strains by comparing images acquired from a specimen at two distinct stress states. Two loading experiments were examined: a pre-cracked, edge-notched specimen, and an uncracked, tensile loaded specimen. Results from the microcracked specimen indicate regions of intense strain localization and a “process zone” at the tip of the microcrack. The analysis of the tensile specimen reveals a highly complex microstructural strain field (caused by uniform tensile loading) attributable to the heterogeneity of the specimen microstructure. It is expected that the use of this technique will allow a greater understanding of bone strength and fracture as well as bone mechanotransduction.

    Keywords:

    cortical bone, micromechanics, microstructure, strain


    Author Information:

    Nicolella, Daniel P.
    Senior Research Engineer, Engineering Technologist, and Director, Southwest Research Institute™, San Antonio, TX

    Nicholls, Arthur E.
    Senior Research Engineer, Engineering Technologist, and Director, Southwest Research Institute™, San Antonio, TX

    Lankford, James
    Senior Research Engineer, Engineering Technologist, and Director, Southwest Research Institute™, San Antonio, TX

    Davy, Dwight T.
    Professor, Case Western Reserve University, Cleveland, OH


    Paper ID: STP42142S

    Committee/Subcommittee: E08.04

    DOI: 10.1520/STP42142S


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