FEM RandbedingungKontakt

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FEM RandbedingungKontakt

Menüeintrag
Modell → Mechanische Randbedingungen → Randbedingung Flächenkontakt
Arbeitsbereich
FEM
Standardtastenkürzel
Keiner
Eingeführt in Version
-
Siehe auch
FEM RandbedingungFixierung

Beschreibung

Erstellt eine FEM-Randbedingung für den Kontakt zwischen zwei Oberflächen.

Anwendung

  1. Es gibt mehrere Möglichkeiten den Befehl aufzurufen:
    • Die Schaltfläche Randbedingung Flächenkontakt drücken.
    • Den Menüeintrag Modell → Mechanische Randbedingungen → Randbedingung Flächenkontakt auswählen.
  2. Die Hauptfläche auswählen.
  3. Die untergeordnete Fläche auswählen.
  4. Die Kontaktsteifigkeit eingeben.
  5. Den Reibungskoeffizient eingeben.

Limitations

  • The contact constraint can only be applied to two faces.
  • Development for multiple contact at once: https://forum.freecadweb.org/viewtopic.php?f=18&t=15699&start=130#p303275
  • Because multiple meshes are currently not supported, contact must be applied to faces that are separated by (at least) a small distance. If the faces were touching (no gap between them), the result of a boolean union or boolean fragments operation (necessary to avoid having multiple meshes which is not allowed at the moment) would be a continuous mesh and thus no need to use contact anymore. See Forum discussion.

Hinweise

Tips for modeling

  • from https://forum.freecadweb.org/viewtopic.php?f=18&p=340874#p340494
  • Better use linear elements otherwise calculations are very time consuming
  • master/slave assignment:
    • The larger of the two surfaces should act as the master surface.
    • If the surfaces are of comparable size, the surface on the stiffer body should act as the master surface.
    • If the surfaces are of comparable size and stiffness, the surface with the coarser mesh should act as the master surface.

CalculiX

  • A very detailed CalculiX contact example. (link)
  • An interesting example found in the FreeCAD German subforum. (link)