title: Spatial resolution and measurement uncertainty of strains in bone and bone-cement interface using digital volume correlation.
abstract: The measurement uncertainty of strains has been assessed in a bone analogue (sawbone), bovine trabecular bone and bone-cement interface specimens under zero load using the Digital Volume Correlation (DVC) method. The effects of sub-volume size, sample constraint and preload on the measured strain uncertainty have been examined. There is generally a trade-off between the measurement uncertainty and the spatial resolution. Suitable sub-volume sizes have been be selected based on a compromise between the measurement uncertainty and the spatial resolution of the cases considered. A ratio of sub-volume size to a microstructure characteristic (Tb.Sp) was introduced to reflect a suitable spatial resolution, and the measurement uncertainty associated was assessed. Specifically, ratios between 1.6 and 4 appear to give rise to standard deviations in the measured strains between 166 and 620 με in all the cases considered, which would seem to suffice for strain analysis in pre as well as post yield loading regimes. A microscale finite element (μFE) model was built from the CT images of the sawbone, and the results from the μFE model and a continuum FE model were compared with those from the DVC. The strain results were found to differ significantly between the two methods at tissue level, consistent in trend with the results found in human bones, indicating mainly a limitation of the current DVC method in mapping strains at this level.
authors.affiliation: Mechanical Behaviour of Materials Laboratory, School of Engineering, University of Portsmouth, Portsmouth PO1 3DJ, UK; Key Laboratory of Pressure Systems and Safety, Ministry of Education; School of Mechanical and Power Engineering, East China University of Science and Technology, Shanghai 200237, China.
authors.forename: Ming-Liang
authors.initials: ML
authors.lastname: Zhu
authors.affiliation: Mechanical Behaviour of Materials Laboratory, School of Engineering, University of Portsmouth, Portsmouth PO1 3DJ, UK.
authors.forename: Qing-Hang
authors.initials: QH
authors.lastname: Zhang
authors.affiliation: Mechanical Behaviour of Materials Laboratory, School of Engineering, University of Portsmouth, Portsmouth PO1 3DJ, UK.
authors.forename: Colin
authors.initials: C
authors.lastname: Lupton
authors.affiliation: Mechanical Behaviour of Materials Laboratory, School of Engineering, University of Portsmouth, Portsmouth PO1 3DJ, UK. Electronic address: jie.tong@port.ac.uk.
authors.forename: Jie
authors.initials: J
authors.lastname: Tong
mesh_terms: D000818:Animals; D001843:Bone Cements; D001842:Bone and Bones / Q000000981:diagnostic imaging; D002417:Cattle; D019245:Compressive Strength; D020342:Finite Element Analysis; D006801:Humans; D011817:Rabbits; D013314:Stress, Mechanical; D035501:Uncertainty; D055114:X-Ray Microtomography
chemical_list: D001843:Bone Cements
keywords: Bone–cement interface; DVC; Sawbone; Spatial resolution; μFE