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Funding Agency:
MHRD
Investigators:
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Dr A. Chawla
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Dr S. Mukherjee
Other Collaborating Agencies:
Project Objective:
The aim of this
project is to establish methodology for building a finite element
model of the human body fidalic to impact conditions. Geometric
information on the human body is to be obtained my taking MRI
scans and recreating 3-D structure by using fast numerical
algorithms for tomography. Material data will be obtained from
existing literature. A finite element mesh is to be generated from
the 3-D structure. The model is to be verified by simulating on a
explicit finite element solver and comparing with experimental
data available in literature.
Highlights of the work:
A successful
finite element code has to reproduce the performance of
calibration tests using reasonable computer resources. This poses
an enormous challenge to impact modeling problems. Excessive
details lead to very small computational time steps for stable
computation, while ignoring critical details lead to loss of
fidelity. Further biomechanical research has not been directed
towards correlating trauma levels during impact, but towards
slower processes like blood flow in veins and arteries and
modeling human gaits.
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Basic anthropomorphic data for humans has been collected for a
sample of US population in various age groups. No such database
exists for the Indian population. We propose to establish
procedure to build such a database from MRI scan data through
tomography. Starting with data on slices, we propose to build 3D
maps of geometry and density in limbs and other organs. This
non-invasive technique will yield in-vivo measures of properties
where none exists for the Indian population.
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The geometry data has to be
converted into a finite element mesh and appropriate material data
like elasticity constants, strain rate data has to be established
for different tissues. The time steps for stable simulation are
dependent on the mesh size as well as material property of the
elements. A balance has to be maintained to obtain fidelity
without increasing the computational time excessively. Instead of
targeting high end processors, we will specifically target
development of models that will execute 400 millisecond of
simulation on a P-IV processor with 2 GB RAM in about three days
time. This should make the model affordable for Indian automobile
and ancillary sectors.
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It will not be feasible to get
data on all age groups of the population or develop and maintain
models for different age groups. It is also proposed to setup
scaling laws and software to generate finite element models to
represent any age group. This will involve simultaneous
modification of geometry, material characteristics and mass
distribution on a master finite element model. To implement this,
the coordinates of each node in the model along with the element
properties have to be modified consistently. There is no software
tool available to carry out this task at present. An object
oriented representation and code to implement the same is
proposed.
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Finite element modeling of human
bones is quite useful in biomechanical simulations. In the present
work a technique is developed to make FE model of bones from MRI/CT
scan data. Developed technique is a modification over
conventionally used techniques. In conventional technique solid
modeling processes intermediate solid / surface generation is
essential before getting finite element model from the scan data.
In the present work this necessity is eliminated and process time
and steps are shortened. Conventional process for finite element
meshing from MRI scan data requires two intermediate steps first
interior and exterior contour point extraction of bones and second
solid modeling from contour data extracted. In the present work an
algorithm is developed and implemented to obtain meshed model of
bones directly from the contours
Related Details
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