FEM Workbench

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Revision as of 22:51, 7 April 2019 by Vocx (talk | contribs) (New section "Extending the FEM Workbench" to document better how the workbench is extended. This information is primarily for power users and developers)

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. Creating a finite element mesh for the geometrical model, or importing it from a different application.
      2. Adding simulation constraints such as loads and fixed supports to the model.
      3. Adding a material to the analysis model.
  2. Solving: solving a system of equations using an external solver from within FreeCAD.
  3. Postprocessing: visualizing the analysis results from within FreeCAD.

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

Element Geometry

Electrostatic Constraints

Fluid constraints

Mechanical constraints

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

Thermal constraints

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.

Menu: Utilities

Context Menu

Preferences

Tutorials

Tutorial 1: FEM CalculiX Cantilever 3D

Tutorial 2: FEM Tutorial

Tutorial 3: FEM Tutorial Python

Tutorial 4: FEM Shear of a Composite Block

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.

Links

FEM Install for a detailed description how to set up a working FEM Module.

FEM Mesh for further Information about the FEM Mesh in FEM Module.

FEM Solver for further Informations about FEM Solvers in FEM Module,

FEM CalculiX for further Information about CalculiX, the most used and best develop solver in FEM Module.

FEM Project for more detailed informations about the Units, Limitations and the Development of FEM Module.

FEM Concrete for informations about analysis's of concrete structures.