SimLab mesh export workflow

Two CAD imports exist:

• File > Import > CAD:

  It allows using the native format (Parasolid, Step, CATIA, ProE…). But the associated software must be installed

• File > Import > CAD: Through Translation:

  It converts and imports the native formats in Step or Parasolid

  Attention: The conversion can generate geometrical errors.

For this import, it is truly advised to choose the conversion in Parasolid:

It gives access to automatic assembly option Imprint solid bodies which has to be checked at the import:

After the import, the components are visible in the data tree. If each component faces define a volume, then the following icon appears:

If faces don’t form a volume, the following icon appears:

The old geometrical components are made invisible, and new components of mesh type are created and visible in the data tree:

All the operations will be applied on those mesh components

If there are components which are not assembled, it is possible to do it manually.

• Use the command Join:

  Assembly > Join (in Connect)

• Check the option General faces to join all type of faces:
  
  
  
  
• Click on Show to visualize the faces to join, and then Join

• Make a re-mesh of all the components to re-mesh correctly the contact area (with the same mesh data as the first mesh):

  Mesh > Re-mesh (in 2D Create)

• Mesh > Edges (in Verify)

  This command allows verifying if the mesh contains free edges (a free edge is an edge belonging to only one surface element) or non-manifold edges (belonging to more than 3 surface elements. This is authorized only in case of internal/shared faces).

  
  
  
  
  
• Mesh > Intersection (in Verify)

  This command allows verifying the intersections between elements

If you want to create the air box in SimLab:

• Choose the bounding box shape (Box or Sphere or Cylinder)

  Here we choose Box shape

• Click on Define > Modify box:
  
  
  
  
• Check Bodies:
  
  
  
  

  Then select all the components (left click). The box appears: it is possible to move a face directly on the graphic (to extend or reduce the box size)

• Validate
• Define element size Mesh size or elements number Number of elements of the bounding box

  Attention: Choose a value close to the value entered for the device (to allow the mesher connecting the elements).
• Validate

A new mesh component Bounding_Box1 is created:

• Verify in the preferences that the option which allows meshing the holes inside a volume is activated:

  File > Preferences button > Mesh:

  check Fill hollow space in solids when volume meshing:

  
  
  
  
  
• If the bounding box "Bounding_Box1" is not in the same node (in data tree) as the device component, make a drag&drop to the same node

• To have a conform mesh, make a Merge+ of all the components (including bounding box):

  Geometry > Merge+ (in Body)

Only one component exists in the data tree:

Mesh > Volume Mesh (in 3D Create)

• Select the mesh order (TET4 for first order and TET10 for second order)
• Define the mean element size
• Choose the volume mesh Internal grading coefficient (1.2 corresponds to a low grading, 2 to a high grading)
• Choose the Quality criteria (Stretch or Aspect ratio or …)
  
  

  

  
  
• Validate the volume mesh

• Make a Merge– on the component:

  Geometry > Merge- (in Body)

The initial components appear:

File > Export > Solver Input File

• Select the components
• Choose the Nastran solver:
  
  
  
  
• A message asking if you want to create and assign properties to components appears: click on Yes:
  
  
  
  

  That allows distinguishing the volumes in Flux

• Choose the name of the .bdf file to export