A study of the progression of damage in an axially loaded Branta leucopsis femur using X-ray computed tomography and digital image correlation

PeerJ. 2017 Jun 23;5:e3416. doi: 10.7717/peerj.3416. eCollection 2017.


This paper uses X-ray computed tomography to track the mechanical response of a vertebrate (Barnacle goose) long bone subjected to an axial compressive load, which is increased gradually until failure. A loading rig was mounted in an X-ray computed tomography system so that a time-lapse sequence of three-dimensional (3D) images of the bone's internal (cancellous or trabecular) structure could be recorded during loading. Five distinct types of deformation mechanism were observed in the cancellous part of the bone. These were (i) cracking, (ii) thinning (iii) tearing of cell walls and struts, (iv) notch formation, (v) necking and (vi) buckling. The results highlight that bone experiences brittle (notch formation and cracking), ductile (thinning, tearing and necking) and elastic (buckling) modes of deformation. Progressive deformation, leading to cracking was studied in detail using digital image correlation. The resulting strain maps were consistent with mechanisms occurring at a finer-length scale. This paper is the first to capture time-lapse 3D images of a whole long bone subject to loading until failure. The results serve as a unique reference for researchers interested in how bone responds to loading. For those using computer modelling, the study not only provides qualitative information for verification and validation of their simulations but also highlights that constitutive models for bone need to take into account a number of different deformation mechanisms.

Keywords: Axial loading; Branta leucopsis; Computer modeling; Constitutive; Deformation mechanisms; Digital image correlation; Modeling and simulation; Progressive damage; Stress–strain; X-ray computed tomography.

Grant support

This work was funded by the Microsoft-BBSRC Dorothy Hodgkin Award FA01546 and the BBSRC grant BB/K006029/1. The X-ray tomography facilities and computer systems used were provided by the Henry Moseley X-ray Imaging Facility at the University of Manchester, UK. The Henry Moseley X-ray Imaging Facilities have been made available through the following EPSRC grants: EP/F007906, EP/F028431, EP/I02249X/1, EP/K004530/1 and EP/M010619/1. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.