Open Source FEM
There is some pretty amazing open source software available for multi-physics FEM.
This blog describes the open source software pulled together to perform FEM (finite element modeling). Originally I used QuickField, student version. However, the limitation on that software is that it is 2D asymmetric or planar with a 250 node limit in the student version. It does however support thermal, electro-statics and magnetics and is quick and good for some small problems.The software described below supports 3D geometry without node limits other than machine memory and it also supports multi-physics. The problems solved can be either steady state or transient. Several packages are required for full end-to-end simulation, all of which are supported Open Source. The software comes with documentation and there are active forums to consult to get questions answered. Best of all the software is free.
Packages
- Salome (for geometry & mesh generation)Â http://www.salome-platform.org
- Elmer (for FEM and post processing)Â http://www.csc.fi/english/pages/elmer
- ParaView (an alternate for post processing)Â http://www.paraview.org
Overview of the process
An overview of the process is that a CAD program, such as TurboCAD Pro, is used to generate a *.step file for each body in the assembly to be modeled. It is important that each 3D model is in the correct location and orientation such that if all *.step files are combined the interface surfaces between bodies seamlessly match. This is a requirement for mesh generation.
Next, Salome is used to import and assign names to each body. There is a web page at ElmerMultiBody that describes the process of creating a multi-body mesh. The combined mesh is exported as a *.UNV file.
Next the program ElmerGrid is used to convert the *.UNV file to a mesh file that can be read by ElmerGui. ElmerGui is used to read in the mesh and create a project file. This is where the type of problem is defined, material properties set and boundary conditions set. Once the project is totally defined the project file can be saved and execution performed through ElmerGui . If ElmerGui is used for post-processing the results can be viewed by launching the post-processor from within the GUI.
If ParaView is used as the post-processor the Elmer project needs to be setup to generate the output Results file for Paraview. The ParaView can be used to view and analyze the results.