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An IGA-FEA model for flexoelectricity-induced healing of microcracks in cortical bone

Witt, Carina ; Kaiser, Tobias and Menzel, Andreas LU (2024) In Computer Methods in Applied Mechanics and Engineering 425.
Abstract

The remodelling process in bones is closely related to electromechanical phenomena. In addition to streaming potentials and piezoelectricity, flexoelectricity has been found to serve as an initiator for remodelling in cortical bone. Since flexoelectricity is coupled to strain gradients, the effect is size-dependent and, accordingly, most relevant on small scales. This means that particularly microcracks which occur in the mechanically loaded bone under daily activity, are healed in response to flexoelectric initiation. More specifically speaking, flexoelectricity induces electric fields in the vicinity of such microcracks and thereby causes osteocyte apoptosis which is a pivotal event in the process of bone remodelling. Since... (More)

The remodelling process in bones is closely related to electromechanical phenomena. In addition to streaming potentials and piezoelectricity, flexoelectricity has been found to serve as an initiator for remodelling in cortical bone. Since flexoelectricity is coupled to strain gradients, the effect is size-dependent and, accordingly, most relevant on small scales. This means that particularly microcracks which occur in the mechanically loaded bone under daily activity, are healed in response to flexoelectric initiation. More specifically speaking, flexoelectricity induces electric fields in the vicinity of such microcracks and thereby causes osteocyte apoptosis which is a pivotal event in the process of bone remodelling. Since experiments on such small scales are difficult to conduct, a numerical framework is established in this contribution which captures the flexoelectric initiation of bone remodelling as well as the remodelling process itself, including bone cell diffusion and progressive crack closure through surface growth. Due to the higher-order PDEs that result from the incorporation of flexoelectricity, a globally C1-continuous isogeometric analysis framework is adopted for the initiation process, whereas a classic finite element approach is proposed for the subsequent diffusion and growth processes. This framework is applied to a cortical bone sample with a narrow microcrack subject to mechanical loading. Growth is coupled to the activity of osteoblasts and incorporated numerically by a moving mesh algorithm. It is shown that the proposed framework can capture the entire process of cortical bone remodelling from its initiation until the successive healing of the microcrack.

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author
; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Bone remodelling, Chemo-electro-mechanical coupling, Flexoelectricity, Isogeometric analysis, Moving mesh, Surface growth
in
Computer Methods in Applied Mechanics and Engineering
volume
425
article number
116919
publisher
Elsevier
external identifiers
  • scopus:85189529837
ISSN
0045-7825
DOI
10.1016/j.cma.2024.116919
language
English
LU publication?
yes
id
8cec0733-4a04-4d07-ac11-5ec0311ec94e
date added to LUP
2024-04-19 11:22:58
date last changed
2024-04-19 11:23:56
@article{8cec0733-4a04-4d07-ac11-5ec0311ec94e,
  abstract     = {{<p>The remodelling process in bones is closely related to electromechanical phenomena. In addition to streaming potentials and piezoelectricity, flexoelectricity has been found to serve as an initiator for remodelling in cortical bone. Since flexoelectricity is coupled to strain gradients, the effect is size-dependent and, accordingly, most relevant on small scales. This means that particularly microcracks which occur in the mechanically loaded bone under daily activity, are healed in response to flexoelectric initiation. More specifically speaking, flexoelectricity induces electric fields in the vicinity of such microcracks and thereby causes osteocyte apoptosis which is a pivotal event in the process of bone remodelling. Since experiments on such small scales are difficult to conduct, a numerical framework is established in this contribution which captures the flexoelectric initiation of bone remodelling as well as the remodelling process itself, including bone cell diffusion and progressive crack closure through surface growth. Due to the higher-order PDEs that result from the incorporation of flexoelectricity, a globally C<sup>1</sup>-continuous isogeometric analysis framework is adopted for the initiation process, whereas a classic finite element approach is proposed for the subsequent diffusion and growth processes. This framework is applied to a cortical bone sample with a narrow microcrack subject to mechanical loading. Growth is coupled to the activity of osteoblasts and incorporated numerically by a moving mesh algorithm. It is shown that the proposed framework can capture the entire process of cortical bone remodelling from its initiation until the successive healing of the microcrack.</p>}},
  author       = {{Witt, Carina and Kaiser, Tobias and Menzel, Andreas}},
  issn         = {{0045-7825}},
  keywords     = {{Bone remodelling; Chemo-electro-mechanical coupling; Flexoelectricity; Isogeometric analysis; Moving mesh; Surface growth}},
  language     = {{eng}},
  month        = {{05}},
  publisher    = {{Elsevier}},
  series       = {{Computer Methods in Applied Mechanics and Engineering}},
  title        = {{An IGA-FEA model for flexoelectricity-induced healing of microcracks in cortical bone}},
  url          = {{http://dx.doi.org/10.1016/j.cma.2024.116919}},
  doi          = {{10.1016/j.cma.2024.116919}},
  volume       = {{425}},
  year         = {{2024}},
}