# Difference between revisions of "FEM Module/zh"

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## Introduction

The FEM Workbench provides a modern finite element analysis (FEA) workflow for FreeCAD. Mainly this means all tools to make an analysis are combined into one graphical user interface (GUI).

## Workflow

The steps to carry out a finite element analysis are:

1. Preprocessing: setting up the analysis problem.
1. Modeling the geometry: creating the geometry with FreeCAD, or importing it from a different application.
2. Creating an analysis.
1. Adding simulation constraints such as loads and fixed supports to the geometric model.
2. Adding materials to the parts off the geometric model.
3. Creating a finite element mesh for the geometrical model, or importing it from a different application.
2. Solving: running an external solver from within FreeCAD.
3. Postprocessing: visualizing the analysis results from within FreeCAD, or exporting the results so they can be postprocessed with another application.

As of FreeCAD 0.15 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

## Menu: Model

• 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.

### Materials

• image is missing Reinforced material: Lets you select reinforced materials consist of a matrix and a reinforcement from the database.

### Mechanical constraints

• Constraint force: Used to define a force in [N] applied uniformly to a selectable face in a definable direction.

## Menu: Mesh

• Nodes set: Creates/defines a node set from FEM mesh.

## Menu: Solve

• Solver Calculix CCX tools: Creates a new solver for this analysis. In most cases the solver is created together with the analysis.

## Menu: Results

• Result show: Used to display the result of an analysis.

## 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 Mesh: further information on obtaining a mesh for finite element analysis.

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.

FEM Project: further information on the unit system, limitations, and the development ideas and roadmap of the workbench.

## 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.

Coupled thermal mechanical analysis tutorials by openSIM

Video tutorial 1: FEM video for beginner (including YouTube link)

Video tutorial 2: FEM video for beginner (including YouTube link)

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.