Test-Bench-Digital-Twin

The process to creating the FEA part of the Digital Twin for the test bench is split into several parts:

• 1. Creating a geometry of the test bench on a CAD software, in our case FreeCAD
• 2. Building a mesh of that geometry, using the built-in Gmesh software/package inside of FreeCAD(but that can also be downloaded as a Python package)
• 3. Applying constraints to that mesh
• 4. Running a FEA solver with the mesh and constraints
• 5. Returning the results as a visual or a spreadsheet

Step 1)

Non-automatable for the moment, except if visualing software is implemented. The geometry file I created with FreeCAD by hand(not code)is the one with the .FCStd extension

Step 2)

Done by the Gmesh package, but user input is recommended, depending on the geometry of your models. FEM example cases(shell, 1D, 2D, symetry...) to be applied in result.

Step 3)

Defined by the user, usually with the GUI or by writing the input files to the solver

Step 4) is the complicated part:

Multiple free FEA solvers exist on the market, all have varying degrees of difficulty and user-friendliness. However, most run on the Linux OS and thus required more computer science knowledge to be executed correctly. In my case, I'm using the default solver in FreeCAD called "CalculiX", which is based of the Abaqus(paid) language. It is one of the most popular FEA solvers because of its easy language and use for strutural analysis.

CalculiX's usage can be decomposed in 3 parts:

• The input file or any file file with the .inp extension
• The application that runs and processes that input file
• The post-processing, or result, files that comes in a variety of forms, but the .frd and .dat files are what interest us for now

The .inp file is generated by FreeCAD quite well, but the functionnalities are limited to static analysis , which is not to interesting, so go to the inp writer README and python to understand what needs to be changed to stick to our problem.

For the second part, I'm trying to understand how to save each step in the memory, if it possible, so we can run Calculix dynamicaly for the step by step analysis.

For the post processing part, I recommend using PreProMax, as it can animate each increment of each step into a movie so you can witness firstand the result.

Step 5)

Therefore solved for the moment with PreProMax, but another GUI could be though of eventually if necessary, like ParaView.