FEM SolverElmer

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Fem-elmer.svg FEM SolverElmer

Menu location
Solve → solver Elmer
Workbenches
FEM
Default shortcut
Introduced in version
-
See also
Solver CalculiX, Solver Z88, FEM tutorial


Description

Elmer is an open source multiphysical simulation software mainly developed by CSC - IT Center for Science (CSC). Elmer development was started 1995 in collaboration with Finnish Universities, research institutes and industry. After it's open source publication in 2005, the use and development of Elmer has become international.

Elmer includes physical models of fluid dynamics, structural mechanics, electromagnetics, heat transfer and acoustics, for example. These are described by partial differential equations which Elmer solves by the Finite Element Method (FEM). https://www.csc.fi/web/elmer

Creating the ElmerSolver object in the Analysis container in FreeCAD, gives access to the Elmer Equations for simple or multiphysical analysis.

Since FreeCAD already has an extensive integration of Calculix and Z88 as solvers for mechanical and thermo-mechanical analysis, Elmer will be preferred for Computational Fluid Dynamics (CFD), Heat, Electrostatics, Magnetostatics and Electrical Forces. It can also be used for mechanical FEA through the Elasticity equation or any combination of the aforementioned equations.

Installation

Elmer requires two components to be interfaced with FreeCAD, ElmerGrid is the interface handling meshes and ElmerSolver is handling the computation. There are standalone programs for both of these applications but their installation and usage are beyond the scope of the FreeCAD integration.

  1. Go to the CSC binaries resources for Elmer: https://www.nic.funet.fi/pub/sci/physics/elmer/bin/ OR https://www.csc.fi/web/elmer/binaries
  2. Download and install the version best suited to your Operating System (Windows 64 bits or Linux)
  3. In FreeCAD go to Edit-->Preferences-->FEM-->Elmer
  4. Link the correct path for both ElmerGrid.exe and ElmerSolver.exe

Elmer Tab in FEM Preferences

You are ready to use Elmer in FreeCAD.

Usage

  1. In FreeCAD go to Workbench FEM.svg FEM workbench
  2. Create an Fem-analysis.svgAnalysis container
  3. Create a FEM Solver for Elmer Fem-elmer.svg A successful analysis will require at least a Model (2D or 3D), a Material (Fluid or Solid, a Mesh, Equations and Boundary conditions Elmer typical file tree.png
  4. Edit the parameters for the solver in the Data tab of the ElmerSolver object in the model tree
  5. Double-click on the ElmerSolver object to prepare an analysis run ElmerSolver TaskPanel.png
  6. Select the path to write the analysis in
  7. Click Write to write the case files in the directory selected previously
  8. Click Run to start the analysis


About Equations:

  • Each type of analysis in Elmer is called an Equation (Flow, Heat, Electrostatics...)
  • One or several equations can be used at once with Elmer by simply adding the Equation object under the ElmerSolver object:
  1. Click on the ElmerSolver object
  2. Select an equation:



Notes

  • Parameters for the Solver and for the Equations are independently set through the Data tab of their respective objects in the tree.
  • Each equation will have a priority, for example, if trying see the effect of a convective flow of hot air, the equation for Flow should be solved with higher priority than Heat, otherwise the solver will first solve Heat through conduction and then Flow.

Documentation

The following link gives access to the full documentation for Elmer https://www.nic.funet.fi/pub/sci/physics/elmer/doc/ This includes the manuals as well as tutorials. Note that documentation and files appended with "gui" generally concern the usage of the Elmer GUI and not the FreeCAD implementation of Elmer.


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