FEM Preferences/it

Other languages:
Display FEM mesh info
FEM

Introduction

Le finestre delle preferenze di FEM si trovano nell'Editor delle Preferenze, Modifica → Preferenze → Fem.

Sono disponibili cinque schede, una per la configurazione generale dell'ambiente.

The currently supported external solvers are:

Generale

On this page you can specify the following:

Name Description
Working directory In what directory the mesh and solver files should be stored
Create mesh groups for analysis reference shapes (highly experimental) If there are several meshes they will be grouped
Keep results on calculation re-run Existing Result objects will be kept, otherwise overwritten by a new solver run
Restore result dialog settings If checked, the Show result dialog is opened with the last used dialog settings
Hide analysis features when opening result dialog The constraints will be hidden in the model view when the Show result dialog is opened
Default solver Default solver to be added when adding an Analysis container. (introduced in version 0.21)

Gmsh

On this page you can specify the following:

Name Description
Search in known binary directories If checked, FreeCAD will look for the binary of Gmsh in known (usual) directories
Gmsh binary path The path to the binary of Gmsh
Log verbosity Log verbosity level: Silent, Errors, Warnings, Direct, Information, Status or Debug. introduced in version 1.1

CalculiX

On this page you can specify the following:

Name Description
Search in known binary directories If checked, FreeCAD will look for the binary of CalculiX in known (usual) directories
ccx binary path The path to the binary of CalculiX
Use internal editor for *.inp files If checked, a built-in *.inp file editor with syntax highlighting is used when editing CalculiX input decks.
External editor The path to the external *.inp file editor.
Split writing of *.inp If checked, multiple *.inp files are written and the main input deck uses the *INCLUDE keywords to reference the other ones. If unchecked, a single large *.inp file is written.
Type Default analysis type: Static, Frequency, Thermomech, Check Mesh or Buckling.
Number of CPU's to use Number of physical processor cores to use for parallel computing.
Matrix solver Default matrix solver: Default, PaStiX, Pardiso, Spooles equation solver, Iterative Scaling or Cholesky iterative solver.
Non-linear geometry If checked, geometric nonlinearity is included by default.
Time incrementation control parameter If checked, uses non-default solver controls (not recommended in most cases).
Maximum number of iterations Maximum number of increments within an analysis step.
Time Initial Step Initial time increment size (can be changed by the solver if automatic incrementation is used).
Time End Total simulated time.
Time Minimum Step Minimum allowable time increment size.
Time Maximum Step Maximum allowable time increment size.
Beam, shell element 3D output format If checked, results for 1D and 2D elements are displayed using 3D representation by default.
Analysis type (transient or steady state) If checked, thermomechanical analyses are of steady-state type by default.
Eigenmode number Default number of requested eigenmodes in frequency analyses.
High frequency limit Default upper limit of evaluated eigenfrequencies in frequency analyses.
Low frequency limit Default lower limit of evaluated eigenfrequencies in frequency analyses.

Elmer

On this page you can specify the following:

Name Description
ElmerGrid: Search in known binary directories If checked, FreeCAD will look for the binary of the grid writer utility of the Elmer in known (usual) directories
ElmerGrid binary path The path to the binary of the grid writer utility of the Elmer
ElmerSolver: Search in known binary directories If checked, FreeCAD will look for the solver binary of Elmer in known (usual) directories
ElmerSolver binary path The path to the solver binary of Elmer
CPU cores to be used The number of CPU cores that will be used to perform the solving.

Important: Elmer divides the mesh into portions. The number of portions is equal to the number of CPU cores used. This can result in side-effects:

  • Depending on your mesh a smaller number of CPU cores can run faster than using more cores.
  • In some cases using e.g. 12 cores does not converge while 8 cores will work fine. The reason is that at some point the mesh portions become too small.

So it is often necessary to adjust the number of cores, depending on the mesh.

Known limitation: For some simulation types you first need to install Elmer modules to enable multi-threading. Check the Elmer report for info about this. A typical case is that for direct solving one has to install the MUMPS module.

Filter results The mesh volume regions processed by each CPU core will be merged to make the volume boundaries invisible.
Use binary format If checked, binary results format is used. Otherwise, ASCII format is used. Binary format may cause lack of results due to a bug. introduced in version 1.1
Save geometry IDs If checked, the index of geometric entities is saved in the results. introduced in version 1.1

Mystran

On this page you can specify the following:

Name Description
Search in known binary directories If checked, FreeCAD will look for the binary of the Mystran in known (usual) directories
Mystran binary path The path to the binary of the Mystran
Write comments to input file

Z88

On this page you can specify the following:

Name Description
Search in known binary directories If checked, FreeCAD will look for the binary named z88r of the Z88 solver in known (usual) directories
z88r binary path The path to the binary named z88r of the Z88 solver
Solver method The solver method used by the Z88 solver for new simulations.
Max places in stiffness matrix This is relevant when the solver method Simple Cholesky is used. After starting the solver, it might tell you that you need to increase the MAXGS value. In this case increase the max places and re-run the solver.
Max places in coincidence vector This is relevant when one of the iterative solver methods is used. After starting the solver, it might tell you that you need to increase the MAXKOI value. In this case increase the max places and re-run the solver.

Netgen

On this page you can specify the following:

Name Description
Legacy Netgen If checked, the legacy Netgen implementation is used by FreeCAD FEM. This might be needed for users (mostly with older and Windows computers) who can't install the Netgen Python bindings necessary for the new implementation. (introduced in version 1.0)


Display FEM mesh info
FEM
FEM

Constraints

User documentation