Biomedical Engineering Reference
In-Depth Information
remeshed operation surface mesh of equilateral triangle is generated. All parameters
are optimized here by optimize-based method using the ratio of the height of the
triangle and the length of its base with quality parameter value above the maximum
threshold 0.3. The various other actions performed in FEA remeshing are:
• Triangle reduction of models normally.
• Improving qualities of the triangles.
• Triangle reduction of models preserving quality.
• Removal of extra shells.
• Self-intersection test to eliminate intersecting triangles completely.
Properties after remeshing of different models:
102094.20 mm
3
,
26160.67 mm
2
,
Model
1—volume
surface
triangles
23816,
points 11952,
Model 2—volume 471900.53 mm
3
, surface 133994.83 mm
2
, triangles 125884,
points 62644,
Model 3—volume 328123.40 mm
3
, surface 115667.27 mm
2
, triangles 128374,
points 63953.
Converted
These models are now imported in ABAQUS 6.10 to convert surface mesh into
volumetric mesh. In mesh tool, choosing edit mesh category and then selecting
convert tri into tetra generates volumetric meshed models. This volumetric
meshing converts triangular elements of surface mesh into four node linear tet-
rahedron elements (C3D4). The three models are meshed with following number
of 3D tetrahedron elements: 268858, 959083, and 809524, respectively. Figure
4
shows volumetric meshed models of femur in ABAQUS. From ABAQUS these
volumetric meshed models are again imported into MIMICS for material assign-
ment. Figure
5
shows volumetric meshed models after they are imported in
MIMICS.
Material Assignment
Once an FE mesh has been generated, the next step is to assign material properties
to the elements. Bone is a biological substance and has complicated mechanical
properties. Femur is a complicated structured material composed of compact bone
and cancellous bone. The compact bone is anisotropic material while cancellous
bone can be considered as isotropic material. Thus, it is difficult to assign material
properties along each direction of bone model. In our study, ten materials are
assigned to all the models using MIMICS. In MIMICS, there are three ways to
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