FEM Install/de

Einführung
Um die Finite Element Analyse (FEA) innerhalb des durchführen zu können, verwendet FreeCAD zwei externe Programme: eines wird für die Generierung des FEM Netzes verwendet, das andere für die numerische Lösung der eigentlichen Analyse. Du kannst testen, ob dein FreeCAD Installation für die FEA bereit ist, indem du das FEM CalculiX Kragarm 3D Beispiel ausführen, das in jeder Installation von FreeCAD seit v0.17 enthalten ist.



FEM Löser
Der Standard Löser zur Durchführung von Finite Elemente Berechnungen ist CalculiX, ein einfacher Löser zur Analyse von Strukturen. FreeCAD schreibt eine CalculiX Eingabedatei, startet den Löser und liest die Ausgabe, die dann visuell im Ansichtsfenster dargestellt werden kann; das bedeutet, dass das CalculiX Binärdatei eigenständig und unabhängig von FreeCAD ist. In Anbetracht der Tatsache, dass es viele Programme gibt, die ein Netz generieren können, ist es empfehlenswert, den Löser zu installieren und sicherzustellen, dass er zuerst funktioniert.

Wenn der Löser korrekt installiert ist, kannst du den einzelnen Befehl im Terminal ausführen, um eine einfache Antwort zu erhalten:

Wenn der Löser installiert ist, stelle sicher, dass der FEM Arbeitsbereich in der Lage ist, die Binärdatei zu finden; gehe zu. Wenn du den Löser selbst kompiliert hast, deaktiviere die Option, und gib den korrekten Pfad zur Binärdatei an. Für andere Löser, die mit FreeCAD verwendet werden können, siehe FEM Löser.

FEM Netz Generator
Um ein FEM Polygonnetz zu erstellen, verwendet FreeCAD Gmsh als Standard Netzerzeuger. Damit dies funktioniert, sollte Gmsh separat von FreeCAD installiert werden.

Wenn das Programm korrekt installiert ist, kannst du den Befehl im Terminal ausführen, um die grafische Oberfläche des Programms zu starten. Diese Oberfläche wird von FreeCAD nicht verwendet, zeigt aber an, dass das Programm installiert ist.

Wenn der Netzerzeuger installiert ist, stelle sicher, dass der FEM Arbeitsbereich in der Lage ist, die Binärdatei zu finden; gehe zu. Wenn du den Löser selbst kompiliert hast, deaktiviere die Option, und gib den korrekten Pfad zur Binärdatei an. Siehe FEM Polygonetz für verschiedene Möglichkeiten, ein gültiges Netz für die Analyse zu erhalten.

Netgen
In previous versions of FreeCAD, Netgen was the default mesher. For it to work with the FEM Workbench, FreeCAD had to be linked against the Netgen libraries at compile time. As FreeCAD transitioned from OCE 0.17 to OCCT 7.1, Netgen 4.9.13 failed to link against this version of OCCT, so it was decided to drop Netgen support in the FEM Workbench (the Netgen button was removed). Nevertheless, shortly afterwards some users reported success in patching Netgen 5.3.1, so that it worked with OCCT 7.x and FreeCAD.

For historical reference, see the threads:
 * (Ubuntu Daily PPA) Transitioning to OCCT7, VTK7...
 * Ubuntu Daily Builds PPA now using OCC 7.1.0
 * patching Netgen 5.3.1 to work with OCCT 7.1
 * Troubles with gmsh in FEM wb (netgen nostalgy)

Despite Netgen not being available from within the FEM Workbench, it can still be used by itself to produce meshes that can then be imported.

If the program is correctly installed, you may run the command in the terminal to launch the graphical interface of the program.

Installing on Windows
The FreeCAD packages available from the download page already include Netgen and CalculiX, so no additional software needs to be installed. Some links where to get better Calculix executable than included in FreeCAD can be found here alternative ccx executables

Installation unter Linux
Linux Distributionen haben unterschiedliche Möglichkeiten, Software zu installieren. Viele Distributionen haben Software Repositorien und Paketmanager; Vor dem kompilieren des Quellcodes, schau in deinem Paketmanager nach, , oder , und installiere diese nach den Anweisungen deiner eigenen Distribution.

Ubuntu PPA
Die freecad-stable und freecad-daily persönlichen Paketarchive (PPA) bieten eine aktuellere Version von FreeCAD als in den offiziellen Ubuntu Repositorien verfügbar ist. Diese PPAs enthalten auch die aktuellsten Pakete, und. Siehe Installieren unter Linux für weitere Informationen zum Einrichten der Repositorien.

If a PPA is already added to your system, install the packages as follows

The freecad-community PPA also provides, , and packages for testing. If they are stable enough, they may be added to the daily or stable repositories. The binaries for ccx 2.14 work on Debian Stretch, but not on Debian Buster due to dependency problems.

the thread Ubuntu Repository discusses the creation of the Ubuntu PPA packages. At the time it was written, CalculiX was not included in the Debian repositories, so there were several personal packages in Launchpad. Only one package should be installed.

Arch Linux
Get the CalculiX package from the AUR repository.

Debian

 * Debian 9 Buster: the packages in the repository are outdated, but you can use the packages from the Ubuntu PPA . See Gmsh 4 package available for testing in Community Extras PPA (forum post).
 * Debian 8 Stretch: the packages in the repository are outdated, but you can use the packages from the Ubuntu PPA . See Gmsh 4 package available for testing in Community Extras PPA (forum post).
 * Debian 7 Jessie: install the packages from Debian 8 Stretch using . See Debian source package for Calculix (forum post).

CalculiX binary
The CalculiX authors provide a pre-compiled Linux binary of the solver; it can be downloaded from the authors' website. However, since different Linux distributions have different library paths, most likely this binary will not work without making some adjustments.

To use the binary with Fedora 21, see the thread Making FEM run on linux fedora 21. For newer Fedora versions, you should compile CalculiX yourself.

If you use this binary, check that the binary is executable, that it is in the executable of your system, and that you have the necessary version of the libraries (,, , etc.) against which it was compiled. This is mentioned in the forum post FEM WB.

Use the command to see the libraries that are linked by the binary. Install any missing dependency.

Compile CalculiX
Since CalculiX is a standalone application, you can either install a binary packaged for your distribution, or compile it yourself. Any CalculiX version from 2.7.x onwards should work with FreeCAD, and since the code hasn't changed much in years, lower versions than 2.7.x may work as well.

Compiling CalculiX is a task for experienced users, requiring editing the Makefiles and build options in different platforms. See the following information:
 * Debian: Debian source package for Calculix, Gmsh 4 package available for testing in Community Extras PPA, Compiling CalculiX ccx on fedora, ubuntu and debian.
 * Fedora 27, 28, 29: Compiling CalculiX ccx on fedora, ubuntu and debian.
 * There is a CMake version of the source package in a github repository, but at the FreeCAD forums no one has reported if this package works.

Compile Netgen
Netgen was originally linked by FreeCAD when FreeCAD used OCE, the community fork of OpenCascade (OCCT). As OCE lagged in development behind OCCT, FreeCAD switched back to OCCT. This broke the linking of Netgen, which could only link against OCCT 6.9 or OCE 0.18 and below. As OCCT 7.x versions improved the core funcitonality of FreeCAD, it was decided to drop Netgen support in favor of Gmsh.

Since then some success has been achieved patching and linking newer versions of Netgen against OCCT 7.x. Nevertheless, the inclusion of Netgen with FreeCAD is still problematic.

Installing on MacOSX
The OSX development packages of FreeCAD may include Netgen but may not include CalculiX.

See this forum post FEM on Mac OSX for information on installing CalculiX, and an updated post for more recent information.

CalculiX: The following posts may be outdated:
 * install CalxiliX with brew
 * FEM on Mac OSX, post 1
 * MacPorts users: CalculiX port test request

Further information
The FEM Workbench is under constant development. The most recent information is found in the FreeCAD forum.

If you have problems installing Netgen, Gmsh, or CalculiX, or another external tool, please search the forum first:
 * netgen site:forum.freecadweb.org
 * gmsh site:forum.freecadweb.org
 * calculix site:forum.freecadweb.org