General Meshing Guidelines

During the CAD modeling process, certain model integrity requirements may not be met, and flaws may go unnoticed. Examples of integrity errors include small gaps, surface slivers, or surface overlaps that can easily be overlooked from the CAD point of view. However, they can be troublesome for mesh creation. To help with successful mesh creation, you can clean up or simplify the model in Simulation Simplify or adjust the meshing parameters.

Simplify the model

Clean up or simplify the model in Simulation Simplify to help the simulation run successfully and more efficiently.

For example:

1. For large assemblies, many of the parts may not play a significant role in the simulation. Perhaps there are parts that do not carry significant loads and are not critical components in terms of structural or thermal integrity for the design. It's better to suppress such parts, since doing so simplifies the meshing process and expedites the simulation process.

2. Parts that have very small features with respect to the overall model dimensions often do not play a substantial role in the simulation results and can be suppressed. An example of small features would be:

   • Very small holes, those with diameters less than 1/100 of the part length.
   • Outer convex rounded corners with small radii.
   • Label imprint and emboss features (such as part numbers or knurling)
   • Small protrusions (such as a timing mark).
   Important: Suppressing such features can simplify the meshing process and reduce the simulation time. However, exercise caution if the small feature might cause a stress concentration effect in a critical stress region.

3. Recreate or modify geometric features to remove narrow sliver surfaces, very short edges, very narrow gaps between edges, and so on. This step helps to improve the quality of the geometry, and therefore simplifies the mesh generation process.

4. In some cases a model may be too complex or have parts with very large volumes that are difficult to solid mesh. Divide the model into less complex parts that can be meshed independently. Use bonded contact between these sub-components to make them behave as a single part.

5. A CAD model may have points at which a mathematical object, like a curved edge or spline, is not defined. These undefined points are called geometric singularities. Examples are an ill-defined tangent point or a curve that crosses itself. Singularities can be problematic for meshing, but they can be eliminated by dividing parts, splitting surfaces, or otherwise modifying the CAD geometry.

6. Models of springs or similar helical structures may mesh better when the long helical face is split. Use a cutting plane on which the helical axis lies. Similarly, complex curved surfaces (like swept splines) or spheres may mesh better when you divide the surfaces into smaller sub-surfaces.

Adjust the Meshing Parameters

You can use the appropriate meshing parameters (options and values) to produce acceptable meshes.

For example:

1. In some cases, due to complex curvature of a model, it is easier to generate a viable mesh by deactivating the Create Curved Mesh Elements option.
2. For assemblies composed of many parts of different sizes, check the Use Part Based Measure for Assembly Mesh option.
3. Choose a mesh size that is small enough to accurately follow the shape of the parts, particularly around small features in critical regions.
4. Rather than making the element size smaller throughout the model, consider applying Local Mesh Controls in critical regions.
5. If you want the solver to identify critical regions and adaptively refine the mesh where appropriate, consider using Adaptive Mesh Refinement. This feature is very useful for ensuring the accuracy of your results.