The mechanical and magnetic behaviour of sintered fibre networks and their suitability for a therapeutic, biomedical application
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Authors
Bosbach, Wolfram A.
Date
2015-09-23Awarding Institution
University of Cambridge
Qualification
PhD
Language
English
Type
Thesis
Metadata
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Bosbach, W. A. (2015). The mechanical and magnetic behaviour of sintered fibre networks and their suitability for a therapeutic, biomedical application (doctoral thesis). https://doi.org/10.17863/CAM.60558
Abstract
Background: Sintered, metallic fibre networks have been used in the design of
a range of technical devices in the past years (e.g. heat exchangers or catalysts).
One potential application in the field of therapeutic, biomedical engineering is
the magnetic-mechanical stimulation of bone growth around prosthetic implants
after joint replacement surgery. The loosening of prosthetic implants in the human
bone is one of the current research topics of prosthesis design. Objectives
and motivation: The present study aims at improving the understanding of
the architecture of sintered fibre networks and their behaviour under mechanical,
or magnetic actuation. The strain field imposed on a bone matrix in the
void network phase is the final focus of the study. Materials and methods: To
achieve the described objectives, 3D scans of sintered, cube-shaped fibre network
samples made from AISI 316L or 444 stainless steel were acquired by means of
computed tomography. Based on the finite element method and beam theory,
the extracted network geometries were run as simulation models locally or on
the Cambridge High Performance Computing Cluster Darwin. Results and
conclusions: The obtained results show that the properties of material architecture
or material mechanics are not constants. Instead, they rather have to
be treated as functions of parameters such as the manufactured fibre volume
fraction, of the available sample size, or of the applied boundary conditions.
The results from the linear, elastic simulation under mechanical actuation were
validated by experimental data. The obtained results identified the material as
being transversely isotropic, the influence of the fibre segment tortuosity on the
material’s Young’s modulus, or fibre deflection (instead of fibre elongation) as
the dominating deformation mechanism within the fibre network samples. The
size of the representative volume element could be determined, which showed
a particular dependency on the applied boundary conditions. Under magnetic
actuation, regions of tension, shear, and compression were obtained for the investigated
samples, with strain peaks located in the free corners of the sample
cubes. The obtained deformation of an inserted bone matrix confirmed that values,
sufficiently large for the intended bone growth stimulation, are achievable
under realistic conditions, with matrix strain peaks in the immediate proximity
to the fibre structure.
Keywords
catalysts, fibre segment tortuosity, fibre networks
Identifiers
This record's DOI: https://doi.org/10.17863/CAM.60558