FEM ConstraintContact
Revision as of 21:26, 13 January 2020 by Kunda1 (talk | contribs) (→Some tipps how to model?: grammar)
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| Menu location |
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| Model → Mechanical Constraints → Constraint contact |
| Workbenches |
| FEM |
| Default shortcut |
| Introduced in version |
| - |
| See also |
| FEM tutorial |
Description
Creates a FEM constraint for contact between 2 surfaces.
How to use
- Click on
or choose Model → Mechanical Constraints → Constraint contact from the top 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:
- A very cool example too. In German supforum.
FEM
- Materials: Solid, Fluid, Nonlinear mechanical; Material editor
- Element geometry: Beam (1D), Beam rotation (1D), Shell (2D), Fluid flow (1D)
Constraints
- Electrostatic: Potential
- Fluid: Initial velocity, Fluid boundary, Flow velocity
- Mechanical: Fixed, Displacement, Plane rotation, Contact, Transform, Force, Pressure, Self weight, Bearing, Gear, Pulley
- Thermal: Initial temperature, Heat flux, Temperature, Heat source
- Solve: Calculix tools, CalculiX, Elmer, Z88; Equations: Heat, Elasticity, Electrostatic, Flux, Flow; Solver: Solver control, Solver run
- Results: Purge, Show; Postprocessing: Apply changes, Pipeline from result, Create warp vector filter, Create scalar clip filter, Create cut filter, Create clip filter, Create data along line filter, Create linearized stresses,
Create data at point filter, Create functions
- Utilities: Clipping plane, Remove clipping planes; Mesh clear, Mesh display info
- Additional: Preferences; FEM Install, FEM Mesh, FEM Solver, FEM CalculiX, FEM Project, FEM Concrete; FEM Element Types
User documentation
- Getting started
- Installation: Download, Windows, Linux, Mac, Additional components, Docker, AppImage, Ubuntu Snap
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- Deprecated or unmaintained workbenches: Complete, Drawing, Robot
- Hubs: User hub, Power users hub, Developer hub
