FEM tutorial

Introduction
! DO NOT TRANSLATE AT THE MOMENT ! This tutorial is meant to introduce the reader to the basic workflow of the FEM Module, as well as most of the tools that are available to perform a static analysis.



Requirements

 * For working with FreeCADs FEM_Module it is STONGLY recommended to use version 0.16 or above.
 * The use of FreeCADs FEM_Module requires the installation of some external software. Check FEM_Install for further install instructions.
 * The reader has the basic knowledge to use the Part and PartDesign Workbenches

Geometrical model
In this example a Cube is used as the study object, but models created in the Part or PartDesign Workbenches can be used instead.


 * 1) Create a new document
 * 2) Activate the Part Workbench
 * 3) Create a Cube by clicking on Create a cube solid.
 * 4) We have a geometrical model to work with right now.

Create an analysis and mesh the geometrical model

 * 1)  Switch to the FEM Workbench
 * 2)  Do NOT select any object neither in tree view nor in model space
 * 3)  Click [[Image:Fem_Analysis.svg|32px]] New mechanical analysis to create a analysis.
 * 4)  An analysis container and a solver object will be created.
 * 5) The analysis should be activated already.
 * 6) If a file is reloaded the analysis has to be activated be right click in tree view before anything could be done in FEM Module.

Material

 * 1) Next step will be to give an material to our model
 * 2) Select [[Image:Fem_Material.svg|32px]] Mechanical material... and choose Steel-generic as the material
 * 3) Click OK

Constraints

 * 1) What needed next is to add some fixed and force constraints to our model.
 * 2) Select [[Image:Fem_ConstraintFixed.svg|32px]] Create FEM fixed constraint
 * 3) Select the bottom face of the Box and click OK
 * 4) Select  [[Image:Fem_ConstraintForce.svg|32px]] Create FEM force constraint
 * 5) Click on Add Reference button in task panel of force constraint.
 * 6) Select the top face of the Box and set the Area load  value to 20 000 N (The unit is fix and will be in Neton at the moment.)
 * 7) Click OK
 * 8) We now have established the restrictions and forces for our static study. What is missing is the FEM Mesh.

FEM Mesh

 * 1) The two possibilities by either the build in mesher Netgen and the external mesher GMSH will be shown in this tutorial. There are varous possibilities to get an valid FEM Mesh. See FEM_Mesh if you are interested in more detailed descriptions.

Netgen

 * 1)  Click on [[Image:Fem_FemMesh.svg|32px]] Create FEM mesh. If you did not change the size of the cube (10, 10, 10) you can leave the settings and click ok.
 * 2) The mesh will be created.
 * 3) The properties of the FEM mesh can be seen in the property editor of FreeCAD.
 * 4) Drag the FEM mesh object inside the Analyis.

GMSH

 * 1) If FreeCADs build in mesher Netgen is not available you will get a popup saying "The FEM module is build without Netgen support ... " The usage of GMSH_macro is recommended, and is used for this example.
 * 2) Start the GMSH macro
 * 3) Select the shape you wish to mesh, in this case our Cube
 * 4) Since we have an analysis object already make sure the box Create Mechanical Analysis from mesh is not activated.
 * 5) Click OK
 * 6) The FEM mesh object will be created.
 * 7) Drag the FEM mesh object inside the Analyis.

Running the Solver

 * 1) Select the solver object  [[Image:Fem_Solver.svg|32px]] of the analysis in tree view and press  [[Image:Fem_QuickAnalysis.svg|32px]] Quick Analysis from the icon tool bar
 * 2) The analysis will be made and the result object should be created.

Analyzing Results

 * 1) Select [[Image:Fem_Result.svg|32px]] Show result
 * 2) Choose among the different Result types to view the results
 * 3) The slider at the bottom can be used to alter the mesh to view the deformation in a simplified manner
 * 4) To remove the results select [[Image:Fem_PurgeResults.png|32px]] Purge results

We are now finished with the basic workflow for the FEM Module.