|Solve → Mechanical equations → Deformation equation
|Introduced in version
|Elasticity equation, FEM tutorial
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.
- 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.
For the general solver settings, see the Elmer solver settings.
The deformation equation provides these special settings:
- DataCalculate Pangle: If the principal angles should be calculated.
- DataCalculate Principal: If all stresses should be calculated.
- DataCalculate Strains: If strains will be calculated. This will also calculate the stresses, even if DataCalculate Principal or DataCalculate Stresses is false.
- DataCalculate Stresses: If stresses should be calculated. Compared to DataCalculate Principal the Tresca yield criterion and the principal stress will not be calculated.
- DataInitialize State Variables: See the Elmer manual for more info.
- DataMixed Formulation: See the Elmer manual for more info.
- DataNeo Hookean Model: Uses the neo-Hookean material model.
- DataVariable: 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 DataMixed Formulation and DataNeo Hookean Model set to true, the variable number must be geometry dimensions + 1, so for 3D geometry the 3 must be changed to 4.
- DataPlane 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:
- Fixed boundary condition
- Displacement boundary condition
- Force load
- Initial temperature condition
- Pressure load
- Gravity load
- 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.
The available results depend on the solver settings. If none of the DataCalculate * settings was set to true, only the displacement is calculated. Otherwise also the corresponding results will be available.