FEM ConstraintContact
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FEM
Документация пользователя
Outdated translations are marked like this.
|
|
| Системное название |
|---|
| FEM ConstraintContact |
| Расположение в меню |
| FEM → Constraint contact |
| Верстаки |
| FEM |
| Быстрые клавиши |
| Нет |
| Представлено в версии |
| - |
| См. также |
| FEM tutorial |
Description
Creates a FEM constraint for contact between 2 surfaces.
Usage
- There are several ways to invoke the command:
- Press the
FEM ConstraintContact button. - Select the Model → Mechanical Constraints → Constraint contact option from the menu.
- Press the
- 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
- 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.
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; 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, Warp filter, Scalar clip filter, Function cut filter, Region clip filter, Line clip filter, Stress linearization plot, Data at point clip 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 Concrete; FEM Element Types
Документация пользователя
- Начинающим
- Установка: Загрузка, Windows, Linux, Mac, Дополнительных компонентов, Docker, AppImage, Ubuntu Snap
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- Верстаки: Std Base, Arch, Draft, FEM, Image, Inspection, Mesh, OpenSCAD, Part, PartDesign, Path, Points, Raytracing, Reverse Engineering, Sketcher, Spreadsheet, Start, Surface, TechDraw, Test Framework, Web
- Не рекомендуемые верстаки: Complete, Drawing, Robot
