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Computational and theoretical contact modelling of hip implant devices with the application of wear simulations
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Ali, Murat (2013) Computational and theoretical contact modelling of hip implant devices with the application of wear simulations. PhD thesis, University of Warwick.
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WRAP_THESIS_Ali_2013.pdf - Submitted Version Download (9Mb) | Preview |
Official URL: http://webcat.warwick.ac.uk/record=b2691640~S1
Abstract
Contact mechanics, wear and tribology of hip implant devices have been studied since early
implantations and the performance of the devices are becoming increasingly important. Wear
and surface damage of these bearing surfaces occur through normal gait loading conditions.
However, in addition to this, stripe wear patterns are observed on patient implant retrievals
and following hip simulator studies. Novel computational and theoretical methods were used
and developed based on advanced computer aided engineering techniques and the finite
element method. Hip joint modelling and numerical methodologies of mechanical wear
simulations were studied through a newly proposed scripting method. Shakedown theory and
maps were referred to for studying the biotribology and contact mechanics of hip resurfacing
devices under cyclic normal, severe and edge loading conditions. Through implicit and
explicit finite element modelling lateral displacement and laxity based microseparation
models were developed. The contact pressure under edge loading conditions was at least a
factor of 2 larger than under normal loading conditions. The wear rates of both the femoral
head and acetabular cup during the bedding-in period were between 1-3 mm3/mc (million
cycles) and 80-110 mm3/mc based on a steady-state wear coefficient. Results showed that
modelling and verifying the contact and stress results under edge loading conditions required
more careful computational modelling than for normal loading conditions. The high contact
pressures observed during simulations of microseparation models were consistent with the
high level of wear and surface damage observed in experimental simulator studies and from
patient retrievals. These methods can therefore be used as a technique to simulate wear of
hip implant devices. Shakedown assessments showed that under normal, as well as edge
loading and severe loading conditions the hip device remained below the elastic shakedown
region of a rolling and sliding shakedown map, which is ideal for minimal surface contact and
subsurface damage.
Item Type: | Thesis (PhD) |
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Subjects: | R Medicine > R Medicine (General) T Technology > TA Engineering (General). Civil engineering (General) |
Library of Congress Subject Headings (LCSH): | Artificial hip joints, Implants, Artificial, Contact mechanics -- Mathematical models, Materials -- Testing -- Computer simulation |
Official Date: | May 2013 |
Institution: | University of Warwick |
Theses Department: | School of Engineering |
Thesis Type: | PhD |
Publication Status: | Unpublished |
Supervisor(s)/Advisor: | Mao, Ken [?] |
Sponsors: | Engineering and Physical Sciences Research Council (EPSRC) |
Extent: | 1 volume (various pagings) : illustrations. |
Language: | eng |
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