Creo Elements/Direct Finite Element Analysis Meshing Guidelines
These guidelines provide some hints and tips on how to speed up meshing and avoid failures.
Hints and Tips
Use part checker:
The part checker will detect corrupt parts and geometrical problems to
a certain extent. This check should always be performed before you generate the mesh.
Avoid modeling inaccuracies:
-
Small edges (approaching the model's resolution) can be a major obstacle for the
mesher. Although in many cases the mesher can deal with this, meshing time
can increase dramatically. Tip: Check min edge/face.
-
Avoid narrow faces and sliver faces
Modeling inaccuracies are the main reason for the mesher to fail. Although they
may not matter so much in the normal design process, they are a major obstacle in FEA
and should therefore be avoided whenever possible.
Simplify the model as much as possible:
Avoid unnecessary details such as blends, holes and other features in areas
where they are not structurally important (*). This issue may not be necessary
for models with little to medium complexity, but is especially important
for parts of high complexity. In any case, simplifying the model will normally
lead to significantly reduced meshing and solving times.
(*) Note: When viewing the results these assumptions need to be verified
whether they are valid.
Check default element size:
In most cases the default element size will produce a good initial mesh
to start with. However, for certain types of parts the suggested element
size may be too fine or too coarse. If a part cannot be meshed, or takes
a very long time to mesh, it is worthwhile checking for a realistic default
element size.
If the average "wall thickness" throughout the part is much thinner
or much thicker than the suggested element size, it is worthwhile adjusting
the default element size manually. A global element size of
0.5 - 2 times the major wall thickness of the part will usually be appropriate.
Usually you can very quickly get visual impression whether a certain
element size will be successful or not. In the AutoMesh dialog you
have a rough estimation for the number of nodes and elements dependent
on the global element size. Check whether the estimated number of elements
is plausible for the complexity of the part.
Known cases where the suggested default element size is inappropriate:
-
Parts with many full cylindrical faces
These tend to produce a mesh that is rather too coarse.
-
Parts with many small edges compared to the overall size and thickness
of the part
The suggested element size can be too small and result into an extremely
large mesh.
This is, for example, often the case for:
- Parts with many imprinted edges
- Parts with many small details
- Parts with many small edges due to modeling inaccuracies.
-
Parts with massive regions and regions with many small details as well
This type of part is usually very difficult too mesh, and is bound
to take long meshing times. The global element size will have to be a compromise
between meeting both types of regions.
Known Problems and How to Avoid Them
Collapsed/Sliver elements:
The mesh that has been generated contains degenerated elements, that do not
meet certain quality criteria, therefore the mesh cannot be used for the
simulation. Often you can "workaround" this by meshing with a different
(in most cases smaller) element size.
Assert error:
As from CoCreate Modeling 8.00, only very few parts show this error. It is a known defect
within the mesher. There is no workaround for this problem unless modifying
the geometry is an option. Sometimes modeling inaccuracies can cause this
problem. Also a STEP export + import is worthwhile trying.