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A Novel Videography Method for Generating Crack-Extension Resistance Curves in Small Bone Samples

DOI: 10.1371/journal.pone.0055641 DOI Help
PMID: 23405186 PMID Help

Authors: Orestis Katsamenis (University of Southampton) , Tomas Jenkins (University of Southampton) , Federico Quinci , Sofia Michopoulou , Ian Sinclair (University of Southampton) , Philipp Thurner (University of Southampton) , Ryan K. Roeder
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Plos One , VOL 8 (2)

State: Published (Approved)
Published: February 2013

Open Access Open Access

Abstract: Assessment of bone quality is an emerging solution for quantifying the effects of bone pathology or treatment. Perhaps one of the most important parameters characterising bone quality is the toughness behaviour of bone. Particularly, fracture toughness, is becoming a popular means for evaluating bone quality. The method is moving from a single value approach that models bone as a linear-elastic material (using the stress intensity factor, K) towards full crack extension resistance curves (R-curves) using a non-linear model (the strain energy release rate in J-R curves). However, for explanted human bone or small animal bones, there are difficulties in measuring crack-extension resistance curves due to size constraints at the millimetre and sub-millimetre scale. This research proposes a novel “whitening front tracking” method that uses videography to generate full fracture resistance curves in small bone samples where crack propagation cannot typically be observed. Here we present this method on sharp edge notched samples (<1 mm×1 mm×Length) prepared from four human femora tested in three-point bending. Each sample was loaded in a mechanical tester with the crack propagation recorded using videography and analysed using an algorithm to track the whitening (damage) zone. Using the “whitening front tracking” method, full R-curves and J-R curves could be generated for these samples. The curves for this antiplane longitudinal orientation were similar to those found in the literature, being between the published longitudinal and transverse orientations. The proposed technique shows the ability to generate full “crack” extension resistance curves by tracking the whitening front propagation to overcome the small size limitations and the single value approach.

Journal Keywords: Bending; Bone Fracture; Tibia; Cameras; Deformation; Mechanical Stress; Behavior; Femur

Subject Areas: Biology and Bio-materials

Instruments: I13-2-Diamond Manchester Imaging