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.
Usage
- Click on
or choose Model → Mechanical Constraints → Constraint contact from the FEM dropdown menu. - Select the master face.
- Select the slave face.
- Enter a contact stiffness.
- Enter a friction coefficient.
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
Notes
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
- 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:
- A very detailed CalculiX contact example. (link)
- A very cool example found in the FreeCAD German subforum. (link)
FEM
- Materials: Solid, Fluid, Nonlinear mechanical, Reinforced (concrete); Material editor
- Element geometry: Beam (1D), Beam rotation (1D), Shell (2D), Fluid flow (1D)
Constraints
- Electromagnetic: Electrostatic potential, Current density, Magnetization
- Geometrical: Plane rotation, Section print, Transform
- Mechanical: Fixed, Displacement, Contact, Tie, Spring, Force, Pressure, Centrif, Self weight
- Thermal: Initial temperature, Heat flux, Temperature, Body heat source
- Overwrite Constants: Constant vacuum permittivity
- Solve: CalculiX Standard, Elmer, Mystran, Z88; Equations: Deformation, Elasticity, Electrostatic, Electricforce, Magnetodynamic, Magnetodynamic 2D, Flow, Flux, Heat; Solver: Solver control, Solver run
- Results: Purge, Show; Postprocessing: Apply changes, Pipeline from result, Warp filter, Scalar clip filter, Function cut filter, Region clip filter, Contours filter, Line clip filter, Stress linearization plot, Data at point clip filter, Filter function plane, Filter function sphere, Filter function cylinder, Filter function box
- Additional: Preferences; FEM Install, FEM Mesh, FEM Solver, FEM CalculiX, FEM Concrete; FEM Element Types
User documentation
- Getting started
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