GuiCommand: Name: FEM EquationDeformation MenuLocation: Solve , Mechanical equations , Deformation equation Workbenches: FEM_Workbench Version: 0.21 SeeAlso: FEM_EquationElasticity, FEM_tutorial
FEM EquationDeformation
Description
This equation describes the nonlinear elastic deformation of solid bodies.
For info about the math of the equation, see the Elmer models manual, section Finite Elasticity.
Usage
- After adding an Elmer solver as described here, select it in the tree view.
- Now either use the toolbar button
or the menu Solve → Mechanical equations → Deformation equation.
- Change the equation\'s solver settings or the general solver settings if necessary.
Solver Settings
For the general solver settings, see the Elmer solver settings.
The deformation equation provides these special settings:
-
Calculate Pangle: If the principal angles should be calculated.
-
Calculate Principal: If all stresses should be calculated.
-
Calculate Strains: If strains will be calculated. This will also calculate the stresses, even if Calculate Principal or Calculate Stresses is false.
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Calculate Stresses: If stresses should be calculated. Compared to Calculate Principal the Tresca yield criterion and the principal stress will not be calculated.
-
Initialize State Variables: See the Elmer manual for more info.
-
Mixed Formulation: See the Elmer manual for more info.
-
Neo Hookean Model: Uses the neo-Hookean material model.
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Variable: The variable for the deformation equation. Change there the 3 to 2 if you have a 2D geometry. For the special case that you have Mixed Formulation and Neo Hookean Model set to true, the variable number must be geometry dimensions + 1, so for 3D geometry the 3 must be changed to 4.
Equation:
- Plane Stress: Computes solution according to the plane stress situation. Applies only for 2D geometry.
Analysis Feature Information
The deformation equation takes the following analysis features into account if they are set:
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[Fixed boundary condition](wiki-test2.php?gitpage=FEM_ConstraintFixed)
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[Displacement boundary condition](wiki-test2.php?gitpage=FEM_ConstraintDisplacement)
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[Force load](wiki-test2.php?gitpage=FEM_ConstraintForce)
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[Initial temperature condition](wiki-test2.php?gitpage=FEM_ConstraintInitialTemperature)
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[Pressure load](wiki-test2.php?gitpage=FEM_ConstraintPressure)
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[Gravity load](wiki-test2.php?gitpage=FEM_ConstraintSelfWeight)
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[Spring](wiki-test2.php?gitpage=FEM_ConstraintSpring)
Note
- Except for calculations in 2D, for all the above analysis features it is important that they act on a face. Features in 3D set to lines or vertices are not recognized by the Elmer solver.
Results
The available results depend on the solver settings. If none of the **Calculate ** settings was set to true*, only the displacement is calculated. Otherwise also the corresponding results will be available.
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This page is retrieved from https://github.com/FreeCAD/FreeCAD-documentation/blob/main/wiki/FEM_EquationDeformation.md