# O modulo FEM

This page is a translated version of the page FEM Workbench and the translation is 0% complete.
Outdated translations are marked like this.
Other languages:

## Introduction

```Bancada FEM proporciona um moderno entorno para o Analise de Elementos finitos (AEF) para FreeCAD. Principalmente isto significa, que todas as ferramentas para realizar o Analise de Elementos Finitos   estão arrumadas no mesmo entorno gráfico (GUI).
```

## Workflow

Os passos para fazer um FEA na bancada de trabalho "FEM Workbench" são:

• Pré-processamento
• A modelagem da geometria, na qual FreeCAD já é um software consolidado.
• Criar uma Análise:
• Criar uma malha FEM fora do modelo geométrico.
• Adicionar restrições tais como cargas e fixar os apoios para o modelo de análise.
• Adicionar um material para o modelo de análise
• Solucionar
• Resolver o sistema de equações de dentro do FreeCAD GUI.
• Pós-processamento

The FEM Workbench can be used on Linux, Windows, and Mac OSX. Since the workbench makes use of external solvers, the amount of manual setup will depend on the operating system that you are using. See FEM Install for instructions on setting up the external tools.

Workflow of the FEM Workbench; the workbench calls two external programs to perform meshing of a solid object, and perform the actual solution of the finite element problem

• Analysis container: Creates a new container for a mechanical analysis. If a solid is selected in the tree view before clicking on it, the meshing dialog will be opened next.

### Geometrical analysis features

• Section print feature: Used to print the predefined facial output variables (forces and moments) to the data file.

### Mechanical boundary conditions and loads

• Rigid body constraint: Used to apply the CalculiX's rigid body constraint that constrains the motion of the nodes of a selected geometrical entity to the motion of a reference point positioned by the user. introduced in version 1.0
• Force load: Used to define a force in [N] applied uniformly to a selectable face in a definable direction.
• Gravity load: Used to define a gravity acceleration acting on a model.

### Overwrite Constants

• FEM mesh region: Creates a localized area(s) to mesh which highly optimizes analysis time.
• FEM mesh group: Groups and labels elements of a mesh (vertex, edge, surface) together, useful for exporting the mesh to external solvers.

• Solver Z88: Creates the solver controller for Z88.

### Electromagnetic equations

• Post pipeline from result: Used to add a new graphical representation of FEM analysis results (color scale and more display options).
• Warp filter: Used to visualize the scaled deformed shape of the model.
• Function cut filter: Used to display the results on a sphere or a plane cutting through the model.
• Region clip filter: Used to clip a field with a sphere or a plane cutting through the model.

### Filter functions

• Plane: Cuts the result mesh with a plane.
• Sphere: Cuts the result mesh with a sphere.

• Clear FEM mesh: Deletes the mesh file from the FreeCAD file. Useful to make a FreeCAD file lighter.
• Display FEM mesh info: Displays basic statistics of existing mesh - number of nodes and elements of each type.

## Obsolete tools

• Fluid boundary condition: Used to define a fluid boundary condition. Did not have a solver. Not available in version 1.0 and above.
• Constraint bearing: Used to define a bearing constraint. Did not have a solver. Not available in version 1.0 and above.
• Constraint gear: Used to define a gear constraint. Did not have a solver. Not available in version 1.0 and above.
• Constraint pulley: Used to define a pulley constraint. Did not have a solver. Not available in version 1.0 and above.
• Nodes set: Creates/defines a node set from FEM mesh. Tool was unfinished and couldn't be used. Not available in version 1.0 and above.

## Information

The following pages explain different topics of the FEM Workbench.

FEM Install: a detailed description on how to set up the external programs used in the workbench.

FEM Geometry Preparation and Meshing: tips regarding geometry preparation for FEM and meshing.

FEM Mesh: details about meshes in the FEM workbench.

FEM Solver: further information on the different solvers available in the workbench, and those that could be used in the future.

FEM CalculiX: further information on CalculiX, the default solver used in the workbench for structural analysis.

FEM Concrete: interesting information on the topic of simulating concrete structures.

## Tutorials

Tutorial 1: FEM CalculiX Cantilever 3D; basic simply supported beam analysis.

Tutorial 2: FEM Tutorial; simple tension analysis of a structure.

Tutorial 3: FEM Tutorial Python; set up the cantilever example entirely through scripting in Python, including the mesh.

Tutorial 4: FEM Shear of a Composite Block; see the deformation of a block that is comprised of two materials.

Tutorial 5: Transient FEM analysis

Tutorial 6: Post-Processing of FEM Results with Paraview

Tutorial 7: FEM Example Capacitance Two Balls; Elmer's GUI tutorial 6 "Electrostatics Capacitance Two Balls" using FEM Examples.

Coupled thermal mechanical analysis tutorials by openSIM

Many video tutorials: anisim Open Source Engineering Software (in German)

## Extending the FEM Workbench

The FEM Workbench is under constant development. An objective of the project is to find ways to easily interact with various FEM solvers, so that the end user can streamline the process of creating, meshing, simulating, and optimizing an engineering design problem, all within FreeCAD.

The following information is aimed at power users and developers who want to extend the FEM Workbench in different ways. Familiarity with C++ and Python is expected, and also some knowledge of the "document object" system used in FreeCAD is necessary; this information is available in the Power users hub and the Developer hub. Please notice that since FreeCAD is under active development, some articles may be too old, and thus obsolete. The most up to date information is discussed in the FreeCAD forums, in the Development section. For FEM discussions, advice or assistance in extending the workbench, the reader should refer to the FEM subforum.

The following articles explain how the workbench can be extended, for example, by adding new types of boundary conditions (constraints), or equations.

A developer's guide has been written to help power users in understanding the complex FreeCAD codebase and the interactions between the core elements and the individual workbenches. The book is hosted at github so multiple users can contribute to it and keep it updated.