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Modelling and numerical simulation of remodelling processes in cortical bone : An IGA approach to flexoelectricity-induced osteocyte apoptosis and subsequent bone cell diffusion

Witt, Carina ; Kaiser, Tobias and Menzel, Andreas LU (2023) In Journal of the Mechanics and Physics of Solids 173.
Abstract

Remodelling is an important process in bones in order to maintain bone mass and to recover cracks which naturally develop within the bone material. There is agreement in the literature that the piezoelectric characteristic of bones is one possible initiator of bone remodelling. In recent experimental studies, however, it has been found that cortical bone also exhibits flexoelectric properties which can, in particular, lead to osteocyte apoptosis through the induction of electric fields and thereby initiate remodelling processes. This is especially the case in the vicinity of micro cracks where large strain gradients are present. In this contribution, a modelling approach for flexoelectricity-induced bone remodelling processes is... (More)

Remodelling is an important process in bones in order to maintain bone mass and to recover cracks which naturally develop within the bone material. There is agreement in the literature that the piezoelectric characteristic of bones is one possible initiator of bone remodelling. In recent experimental studies, however, it has been found that cortical bone also exhibits flexoelectric properties which can, in particular, lead to osteocyte apoptosis through the induction of electric fields and thereby initiate remodelling processes. This is especially the case in the vicinity of micro cracks where large strain gradients are present. In this contribution, a modelling approach for flexoelectricity-induced bone remodelling processes is presented. Due to the higher-order nature of the flexoelectric effect, isogeometric analysis is employed for a globally C1-continuous approximation of the displacement field. The bone cells mainly involved in the remodelling process – osteocytes, osteoclasts and osteoblasts – are accounted for by the introduction of additional field variables so that the model includes chemo-electro-mechanical coupling. The migration of the latter two cell types is modelled by non-linear diffusion equations with generally anisotropic evolving diffusion tensors. It is shown that the proposed modelling approach can capture how flexoelectricity leads to osteocyte apoptosis in the vicinity of micro cracks and how bone cells subsequently move towards the remodelling site in response to particular signalling mechanisms. The simulation results indicate that, due to the size-dependency of the flexoelectric effect, its relevance with regard to bone remodelling increases on smaller scales and can potentially exceed piezoelectric influences.

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author
; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Bone remodelling, Chemo-electro-mechanical coupling, Diffusion, Electroelasticity, Flexoelectricity, Isogeometric analysis
in
Journal of the Mechanics and Physics of Solids
volume
173
article number
105194
publisher
Elsevier
external identifiers
  • scopus:85146900641
ISSN
0022-5096
DOI
10.1016/j.jmps.2022.105194
language
English
LU publication?
yes
id
865e090c-ca40-47d0-aeb4-c6811a9b360b
date added to LUP
2023-02-10 14:16:39
date last changed
2023-02-10 14:16:39
@article{865e090c-ca40-47d0-aeb4-c6811a9b360b,
  abstract     = {{<p>Remodelling is an important process in bones in order to maintain bone mass and to recover cracks which naturally develop within the bone material. There is agreement in the literature that the piezoelectric characteristic of bones is one possible initiator of bone remodelling. In recent experimental studies, however, it has been found that cortical bone also exhibits flexoelectric properties which can, in particular, lead to osteocyte apoptosis through the induction of electric fields and thereby initiate remodelling processes. This is especially the case in the vicinity of micro cracks where large strain gradients are present. In this contribution, a modelling approach for flexoelectricity-induced bone remodelling processes is presented. Due to the higher-order nature of the flexoelectric effect, isogeometric analysis is employed for a globally C<sup>1</sup>-continuous approximation of the displacement field. The bone cells mainly involved in the remodelling process – osteocytes, osteoclasts and osteoblasts – are accounted for by the introduction of additional field variables so that the model includes chemo-electro-mechanical coupling. The migration of the latter two cell types is modelled by non-linear diffusion equations with generally anisotropic evolving diffusion tensors. It is shown that the proposed modelling approach can capture how flexoelectricity leads to osteocyte apoptosis in the vicinity of micro cracks and how bone cells subsequently move towards the remodelling site in response to particular signalling mechanisms. The simulation results indicate that, due to the size-dependency of the flexoelectric effect, its relevance with regard to bone remodelling increases on smaller scales and can potentially exceed piezoelectric influences.</p>}},
  author       = {{Witt, Carina and Kaiser, Tobias and Menzel, Andreas}},
  issn         = {{0022-5096}},
  keywords     = {{Bone remodelling; Chemo-electro-mechanical coupling; Diffusion; Electroelasticity; Flexoelectricity; Isogeometric analysis}},
  language     = {{eng}},
  publisher    = {{Elsevier}},
  series       = {{Journal of the Mechanics and Physics of Solids}},
  title        = {{Modelling and numerical simulation of remodelling processes in cortical bone : An IGA approach to flexoelectricity-induced osteocyte apoptosis and subsequent bone cell diffusion}},
  url          = {{http://dx.doi.org/10.1016/j.jmps.2022.105194}},
  doi          = {{10.1016/j.jmps.2022.105194}},
  volume       = {{173}},
  year         = {{2023}},
}