Age-related properties at the microscale affect crack propagation in cortical bone

Forskningsoutput: TidskriftsbidragArtikel i vetenskaplig tidskrift

Abstract

The increased risk for fracture with age is associated not only with reduced bone mass but also with impaired bone quality. At the microscale, bone quality is related to porosity, microstructural organization, accumulated microdamage and intrinsic material properties. However, the link between these characteristics and fracture behavior is still missing. Bone tissue has a complex structure and as age-related compositional and structural changes occur at all hierarchical length scales it is difficult to experimentally identify and discriminate the effect of each mechanism. The aim of this study was therefore to use computational models to analyze how microscale characteristics in terms of porosity, intrinsic toughness properties and microstructural organization affect the mechanical behavior of cortical bone. Tensile tests were simulated using realistic microstructural geometries based on microscopy images of human cortical bone. Crack propagation was modelled using the extended finite element method where cement lines surrounding osteons were modelled with an interface damage law to capture crack deflections along osteon boundaries. Both increased porosity and impaired material integrity resulted in straighter crack paths with cracks penetrating osteons, similar to what is seen experimentally for old cortical bone. However, only the latter predicted a more brittle failure behavior. Furthermore, the local porosity influenced the crack path more than the macroscopic porosity. In conclusion, age-related changes in cortical bone affect the crack path and the mechanical response. However, increased porosity alone was not driving damage in old bone, but instead impaired tissue integrity was required to capture brittle failure in aging bone.

Detaljer

Författare
Enheter & grupper
Forskningsområden

Ämnesklassifikation (UKÄ) – OBLIGATORISK

  • Teknisk mekanik

Nyckelord

Originalspråkengelska
Artikelnummer109326
TidskriftJournal of Biomechanics
Volym95
Tidigt onlinedatum2019
StatusPublished - 2019
PublikationskategoriForskning
Peer review utfördJa

Relaterad forskningsoutput

Anna Gustafsson, 2019 nov 11, Department of Biomedical Engineering, Lund university. 178 s.

Forskningsoutput: AvhandlingDoktorsavhandling (sammanläggning)

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