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Diplom- und Master-Arbeiten (eigene und betreute):

L. Peyker:
"A Feasibility Study of a Bone-Screw MicroFE Model";
Betreuer/in(nen): D. H. Pahr; Institut für Leichtbau und Struktur-Biomechanik, TU Wien, 2012; Abschlussprüfung: 25.01.2012.



Kurzfassung englisch:
The finite element method is increasingly employed in biomechanical investigations. This thesis takes the example of the volar plate osteosynthesis of the human radius as a starting point for a comparison between FE analysis and a mechanical test. A simple model of a titanium screw which was implanted in a cropped bone sample and subjected to a defined displacement was derived. Five different FE configurations were created from CT data and compared to test results. These FE models were used to study the influence of the contact between bone and screw as well as the feasibility of a virtually inserted screw. The effect of the implantation process on the FE model generation was also discussed. Furthermore, the influence of the resolution of the CT data on the FE results was studied.

This thesis shows that linear microFE modelling of the screw/bone interface leads to an over-estimation of the spring stiffness of the connection in comparison to the data from the mechanical test. Different modelling strategies were used to investigate this effect. One model with perfect bonding between bone and screw gives a stiffness overestimation of 67%. Another model that takes the contact between bone and screw into account gives a reduction of this over-estimation to 41%. Additionally, revmoving those trabeculae from the model that were broken during the implantation process leads to a further decrease in spring stiffness (3% over-estimation). On the other hand, the model created by virtually inserting the screw gives a spring stiffness that is 89% higher than the measured value from the mechanical test.

In conclusion, microFE models are well suited for the investigation of bone/screw models, however non-linear considerations will be needed to improve the predictability.

Erstellt aus der Publikationsdatenbank der Technischen Universität Wien.