FEM tutorial

Introduction
This tutorial is meant to introduce the reader to the basic workflow of the FEM Workbench, as well as most of the tools that are available to perform a static analysis.



Requirements

 * FreeCAD version 0.16 or above
 * Netgen and/or GMSH is installed on the system
 * In the case of GMSH, installation of psicofil's macro is recommended
 * Calculix is installed on the system
 * The reader has the basic knowledge to use the Part and PartDesign Workbenches

Modeling
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

Now we have a model with which to work with.

Meshing the model

 * 1) Switch to the FEM Workbench

Netgen

 * 1) Select the model
 * 2) Select [[Image:Fem_FemMesh.svg|32px]] Create FEM mesh
 * 3) Click Ok
 * 4) Select the Mesh from the Tree View
 * 5) Click [[Image:Fem_Analysis.svg|32px]] New mechanical analysis from the menu to create an analysis from the mesh that was created.

You can also drag and drop a mesh to a Mechanical Analysis that does not have a mesh within the Tree View.

GMSH
The usage of psicofil's macro is recommended, and is used for this example.
 * 1) Activate the macro
 * 2) Select the object you wish to use, in this case our Cube
 * 3) Check the box Create Mechanical Analysis from mesh
 * 4) Click OK

We have now meshed our object and are ready to add constraints and forces.

Constraints and Forces

 * 1) Hide the mesh from the Tree View.
 * 2) Show the original model
 * 3) Select [[Image:Fem_ConstraintFixed.svg|32px]] Create FEM fixed constraint
 * 4) Select the bottom face of the Box and click OK
 * 5) Select  [[Image:Fem_ConstraintForce.svg|32px]] Create FEM force constraint
 * 6) Select the top face of the Box and set the Area load  value to 20 000
 * 7) Click OK

We now have established the restrictions and forces for our static study.

Final preparations

 * 1) Select [[Image:Fem_Material.svg|32px]] Mechanical material... and choose Steel-generic as the material
 * 2) Click OK

Running the Solver

 * 1) Select  [[Image:Fem_NewAnalysis.svg|32px]] Start calculation from the menu
 * 2) Select Write Calculix Input File
 * 3) Select Run Calculix
 * 4) Click Close

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.