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DISSERTATIONS
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Author: |
Karatsis Evagelos |
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Title: |
Analysis
of tomography data and modelling of human body |
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Abstract: |
Biomechanics
field has three crucial characteristics which separate it from the
“conventional” knowledge fields. First the subjects of study are
usually living systems with time-varying properties. Second is that
access to such systems is allowed only through non-destructive
methods and in short period of time to ensure that the properties
will not alter significantly. But experience has shown that the use
of non-destructive methods for measurements and diagnosis is
time-consuming and unfriendly to the researcher-engineer. The third
is related to the uniqueness of each living system. Despite the fact
that living systems may share common geometric characteristics, it
was never observed in nature the existence of two geometrically
identical living systems. This means that if we want to conduct
simulations for two living systems, for example femoral bones, even
though their geometrical differences might be insignificant, the
modelling process should be repeated. The investigation of the
reduction of the required time for a simulation in the field of
biomechanics, through the personalization of the process and its
simplification with the aid of automations, is the subject of the
current doctoral thesis.In more detail the current doctoral thesis
investigates all aspects of modelling in the field of biomechanics,
starting from the early stage of the CT Scanning until the ready to
run solver file, in order to identify the steps that are time
consuming. Then, to address these problems, it is proposed a new
modelling process. The main idea of the proposed modelling process
is the exploitation of the repeated geometric patterns of living
systems and for the first time it is made a proposal of all the
characteristics of the system within which the new process can be
materialized. This is achieved initially with the recognition of the
geometrical features and then the classification of the living
systems in a database based on them. For the first time specific
feature lines are proposed and code names are assigned to them.
Consequently those feature lines are used for the automated finding
of a geometrically compatible template finite element model, with
the subject of study, through a fast and simple three stage process
(1.Code name, 2.Length of feature line, 3.Area between the main
feature line of the template model and the corresponding of the
subject of study). Finally these curves are used by the proposed
morphing algorithms that affect the finite element mesh with
ultimate goal the matching of the geometry of the preexisting
template model to the geometry of the subject of study. In this way
the reusability and personalization of template models of living
systems is achieved, while simultaneously the most time consuming
steps of the modelling process are avoided such as the creation of
the three dimensional geometry out of the CT scan. |
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