FEM EquationDeformation

Description
This equation describes the nonlinear elastic deformation of rigid bodies.

For info about the math of the equation, see the Elmer models manual, section Finite Elasticity.

Usage

 * 1) After adding an Elmer solver as described here, select it in the tree view.
 * 2) Now either use the toolbar button [[Image:FEM_EquationDeformation.svg|24px]] or the menu.
 * 3) 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:
 * : If the principal angles should be calculated.
 * : If all stresses should be calculated.
 * : If strains will be calculated. This will also calculate the stresses, even if or  is false.
 * : If stresses should be calculated. Compared to the Tresca yield criterion and the principal stress will not be calculated.
 * : See the Elmer manual for more info.
 * : See the Elmer manual for more info.
 * : Uses the neo-Hookean material model.
 * : The variable for the elasticity equation. Change there the 3 to 2 if you have a 2D geometry. For the special case that you have and  set to true, the variable number must be geometry dimensions + 1, so for 3D geometry the 3 must be changed to 4.

Equation:
 * : Computes solution according to the plane stress situation. Applies only for 2D geometry.

Constraint Information
The elasticity equation takes the following constraints into account if they are set:


 * [[Image:FEM_ConstraintFixed.svg|32px]] Constraint fixed
 * [[Image:FEM_ConstraintDisplacement.svg|32px]] Constraint displacement
 * [[Image:FEM_ConstraintForce.svg|32px]] Constraint force
 * [[Image:FEM_ConstraintInitialTemperature.svg|32px]] Constraint initial temperature
 * [[Image:FEM_ConstraintPressure.svg|32px]] Constraint pressure
 * [[Image:FEM_ConstraintSelfWeight.svg|32px]] Constraint self weight
 * [[Image:FEM_ConstraintSpring.svg|32px]] Constraint spring

Note

 * Except for calculations in 2D, for all above constraints it is important that they act on a face. Constraints for 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 settings was set to true, only the displacement is calculated. Otherwise also the corresponding results will be available.