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The mars.out file should be renamed to something more descriptive and should be
edited so that the names of the lists are meaningful and unique.
Note. INGRID should be used mostly as a mesh generator. Some of the features
in INGRID are not translated into MARS. For example, contact conditions specified in
INGRID are not translated because MARS deals with contact at the list level (nodes
from list A contacting faces from list B) and not at the object level (nodes, faces). Here
is a partial list (to be complete) of features that are supported:
- node boundary conditions,
- solid elements
- shell elements
- beam elements
- load curves
- pressure faces
The aspect ratio of Ingrid meshes can be improved by moving the internal nodes.
The example in Figure a) at the website page
http://www.es3inc.com/mechanics/MARS/Online/HowTo.htm#_How_to_convert
shows the mesh of a bullet generated using Ingrid. Note that the aspect ratio of some
element (2 elements deep from the surface) can be improved by slightly moving the nodes.
This is done in MARS by using the Smooth command after the mesh has been imported
and before it is saved. The improved mesh after a series of 6 smooth commands is shown
in Figure b).
HexSolidList H000 {
Rename BLLT
Smooth
Smooth
. . .
Write PartMeshDataFile bullet.mrs
}
In the smoothing operations above, the displacements of the surface nodes are constrained
to ensure that the external shape does not change. Thi is done by using nodal boundary
conditions. The Ingrid input for the model above is listed below. Note how boundary
conditions are used to fix the external nodes. Nodes at the bottom face are free to move
in the bottom plane. Nodes on the plane of symmetry are free to move within the plane
of symmetry. The boundary conditions need to be modified for the actual simulation.
Bullet
dn3d
mat 1 3
ro 0.00025 e 10e6 pr 0.3
endmat
start
1 3 5 ; 1 3 5 7 9 ; 1 7 9 11 ;
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