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

Abstract

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. (2017), A study of the progression of damage in an axially loaded Branta leucopsis femur using X-ray computed tomography and digital image correlation. PeerJ 5:e3416;

X-ray computed tomography in life sciences

“…These techniques have also been applied to tissues that require mechanical stress for homeostasis, such as musculoskeletal tissues [25], or respond to internal pressure, such as arteries [34]. Mechanical loading studies are also of interest for investigating damage to tissues [100], or the damage tolerance of an implanted device [26], for instance.…”

Four-Dimensional Imaging of Soft Tissue and Implanted Biomaterial Mechanics: A Barbed Suture Case Study for Tendon Repair

“…XμCT can now be performed at spatial resolutions of <50 nm, and when used in tandem with traditional techniques such as histology, energy-dispersive X-ray spectrometry, scanning electron microscopy, or transmission electron microscopy, a wealth of 3D structural and compositional data can be obtained . This is furthered by the potential of using XμCT to inform FE modeling, obtaining quantitative stress and strain data, which is becoming commonplace in osteoporotic bone density and strength studies , and can be validated using time-lapse tomography . These advancements have culminated in the timely potential to concurrently interrogate the morphology, composition, and mechanical response of soft tissue implants in situ using multimodal techniques which we describe herein.…”

“…7 This is furthered by the potential of using XμCT to inform FE modeling, obtaining quantitative stress and strain data, which is becoming commonplace in osteoporotic bone density and strength studies 8,9 and can be validated using time-lapse tomography. 10 These advancements have culminated in the timely potential to concurrently interrogate the morphology, composition, and mechanical response of soft tissue implants in situ using multimodal techniques which we describe herein. It is with this recent advancement in CT resolution and contrast agent development that this case study has been performed to demonstrate the capability in the biomaterial arena.…”