FEM ConstraintContact: Difference between revisions

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{{Docnav|[[FEM_ConstraintPlaneRotation|Constraint plane rotation]]|[[FEM_ConstraintTransform|Constraint transform]]|[[FEM_Module|FEM]]|IconL=FEM_ConstraintPlaneRotation.png|IconC=Workbench_FEM.svg|IconR=FEM_ConstraintTransform.png}}

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{{GuiCommand|Name=FEM ConstraintContact|MenuLocation=Model → Mechanical Constraints → Constraint contact||Workbenches=[[Fem Workbench|FEM]]|Shortcut=|SeeAlso=[[FEM_tutorial|FEM tutorial]]}}
{{GuiCommand|Name=FEM ConstraintContact|MenuLocation=Model → Mechanical Constraints → Constraint contact||Workbenches=[[Fem Workbench|FEM]]|Shortcut=|SeeAlso=[[FEM_tutorial|FEM tutorial]]}}
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#The contact constraint can only be applied to two faces.
#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


==Notes== <!--T:5-->
==Notes== <!--T:5-->
=== Some tipps how to model? ===
* 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.


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#The contact stiffness should be 10 times the young's modulus of the material for hard contact. The higher the value for contact stiffness, the harder the contact between surfaces.
#The slave face is the face which penetrates into the master face, and therefore experiences more deformation.
#The *CONTACT PAIR card is used for modeling contact in CalculiX. The constraint uses Face-to-Face penalty contact and the contact formulation is explained in detail at http://web.mit.edu/calculix_v2.7/CalculiX/ccx_2.7/doc/ccx/node112.html


=== CalculiX === <!--T:9-->
* The contact stiffness should be 10 times the young's modulus of the material for hard contact. The higher the value for contact stiffness, the harder the contact between surfaces.
* The slave face is the face which penetrates into the master face, and therefore experiences more deformation.
* The *CONTACT PAIR card is used for modeling contact in CalculiX. The constraint uses Face-to-Face penalty contact and the contact formulation is explained in detail at http://web.mit.edu/calculix_v2.7/CalculiX/ccx_2.7/doc/ccx/node112.html
* Overview for different contact types: https://forum.freecadweb.org/viewtopic.php?f=18&t=15699&start=90#p188736
* Further interesting informations:
** https://forum.freecadweb.org/viewtopic.php?f=18&t=23102#p180709 and following posts !!!
** https://forum.freecadweb.org/viewtopic.php?f=18&t=20276
** https://forum.freecadweb.org/viewtopic.php?f=18&t=21331
** https://forum.freecadweb.org/viewtopic.php?f=18&t=15699 (initial contact topic)

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* A very detailed CalculiX contact example:
** http://dip28p.web.fc2.com/calculix/netgen2calculix/index.html

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* A very cool example too. In German supforum.
** https://forum.freecadweb.org/viewtopic.php?f=13&t=39663&start=10#p337254

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{{Docnav|[[FEM_ConstraintPlaneRotation|Constraint plane rotation]]|[[FEM_ConstraintTransform|Constraint transform]]|[[FEM_Module|FEM]]|IconL=FEM_ConstraintPlaneRotation.png|IconC=Workbench_FEM.svg|IconR=FEM_ConstraintTransform.png}}

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Revision as of 08:13, 14 October 2019

FEM ConstraintContact

Menu location
Model → Mechanical Constraints → Constraint contact
Workbenches
FEM
Default shortcut
None
Introduced in version
-
See also
FEM tutorial

Description

Creates a FEM constraint for contact between 2 surfaces.

How to use

  1. Click on or choose ModelMechanical Constraints Constraint contact from the top menu.
  2. Select the master face.
  3. Select the slave face.
  4. Enter a contact stiffness.
  5. Enter a friction coefficient.

Limitations

  1. The contact constraint can only be applied to two faces.
  2. development for multiple contact at once: https://forum.freecadweb.org/viewtopic.php?f=18&t=15699&start=130#p303275

Notes

Some tipps how to model?

  • 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