FreeCAD Von Mises (fcVM) FEM Workbench

Finite element collapse analysis based on the von Mises plasticity model for use with FreeCAD

Background

fcVM is a finite element workbench and solver for performing collapse analysis of structures and soil bodies. It is based on the theory of elastoplasticity and gives insight in ductility and reserve strength beyond first yield. The theory underpinning fcVM can be found in the document included in this repository.

Prerequisites

• FreeCAD >= v0.19

Installation

Manual Install

1. Create a fcVM-workbench directory in the FreeCAD Mod/ directory.
   • Tip: the location of which can be found by typing App.getUserAppDataDir() in the FreeCAD python console.
2. Copy the entire fcVM-workbench repository into this new fcVM-workbench directory.
3. Restart FreeCAD

Result: If all went well, the fcVM workbench should now be an option in the FreeCAD workbench dropdown menu.

App.getUserAppDataDir()
├── Mod
│   ├── fcVM-workbench
│   │   ├── control files
│   │   │   ├── Block_Disp_Control_Example.inp
│   │   │   └── etc.
│   │   ├── documentation
│   │   │   └── Numerical Analysis of Soil Structure Interaction HvL.PDF
│   │   ├── freeCAD files
│   │   │   ├── Block_Disp_Control_Example.FCStd
│   │   │   └── etc.
│   │   ├── icons
│   │   │   └── fcFEM.svg
│   │   ├── output files
│   │   │   ├── Block_Disp_Control_Example.out
│   │   │   └── etc.
│   │   ├── pictures
│   │   │   ├── Embankment_with_Ditch_Example_Failure_Mechanism.png
│   │   │   └── etc.
│   │   ├── source code
│   │   │   ├── .gitignore
│   │   │   ├── fcVM.FCMacro
│   │   │   └── fcVM.py
│   │   ├── user_interface
│   │   │   └── fcVM.ui
│   │   ├── .gitignore
│   │   │
│   │   ├── Init.py
│   │   │
│   │   ├── InitGui.py
│   │   │
│   │   ├── README.md
│   │   │
│   │   └── dummy.py
│   │

Dependencies

fcVM imports (from) the following packages:

numpy
scipy (version 1.11.3)
numba
matplotlib
scikit-sparse
pyvista
meshio

Linux & MacOS

Depedencies can be installed with the usual package managers (e.g. conda or mamba).

Windows

On Windows delendency installation requires some extra steps:

1. Download Miniforge3: Miniforge3
2. Run the installer: Miniforge3-Windows-x86_64.exe
3. Find and run Miniforge on your system - this opens a Miniforge Prompt: (base) C:"path">
4. Create a new virtual environment:
   (base) C:"path"> mamba create --name fcVM (or any other name of your choice)
5. Change into the new environment:
   (base) C:"path"> mamba activate fcVM (or the another name of your choice)
6. Install FreeCAD and dependencies:
   (fcVM) C:"path"> mamba install freecad scipy=1.11.3 numba matplotlib scikit-sparse pyvista meshio (with spaces and no commas)
7. Check with python if the dependencies can be imported
   (fcVM) C:"path"> python
   >>> import scipy.sparse
   >>> import sksparse.cholmod
8. If no problems present, quit python and start freecad:
   (fcVM) C:"path"> freecad
9. If you encounter a "black screen" then follow the advice here, i.e. rename all opengl32sw.dll files on your system to opengl32.dll.

Documentation

Please refer to source code for in-line comments and to the FreeCAD forum (TBC)

Current Limitations

fcVM only works with 2nd order volumetric meshes generated with GMSH or Netgen (10-noded tetrahedrals).

Licence information

Copyright (c) 2024 - Harry van Langen [email protected]

This program is free software; you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License (LGPL)
as published by the Free Software Foundation; either version 2 of
the License, or (at your option) any later version.
for detail see the LICENCE text file.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU Library General Public License for more details.

You should have received a copy of the GNU Library General Public
License along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
USA