I have been using freecad for some basic FEA.
I am wanting to know what the best work flow for a beginner in FEA would be?
All in freecad
mesh the object in freecad, export, then use calculix
model in freecad>mesh in gmesh>solve with calculix
If its the 3rd or 2nd options, do you have any recomended videos i shoudl watch? I have searched for some but there are so many, im not sure what to filter out. Bad practice does not make perfect or as i say GIGO - garbage in garbage out : )
end goal is to have visuals, etc
Also, can calculix do cycles to failure? I might have to use fatlab for that
there is another workflow option:
model in freecad , mesh and solve with prepomax,
maybe these is for beginning best option,
starting with calculix i recommend your these example:
and these of course:
This prepomax, can it do FEA and CFD or is it just FEA? I am new to both : )
I have not heard of it or used it.
This might be a decent work flow. I do have openfoam installed but have not used it yet. I was going to use openfaom via the CFD workbench in freecad
thanks for the information.
It depends on what you need. Sometimes the FEM module in FreeCAD is sufficient (for simple analyses, maybe with small keyword edits). ParaView can add more postprocessing tools to that.
In many cases, you will find PrePoMax enough for your purposes. But you may need even more and then you may have to add manual keyword edits to that as well.
If you are Linux user and/or want more control with API and easy access to input deck, GraphiX and other simple preprocessing tools for CalculiX might be a good idea.
When it comes to fatigue, CalculiX only has fatigue crack propagation procedure so yes - you may want to use Fatlab. Or check Code_Aster.
so let me ask this, are you saying i can take a solved FEA scenario in freecad, and some how put it in paraview to view the results?
When you say “keyword edits” what does that mean?
I have used linux back when i was a CCNP and RHCT, but now i am an aerospace engineering student . CFD was an elective that is now not offered anymore, but i want to learn. I missed it because it was a new university and i was a new student so i did not have the background in fluids yet. So now i am trying to learn on my own.
I wouldnt mind learning how to use paraview or prepomax to mesh a 3d object i made in freecad, then use prepomax to solve it. I also want to learn how to take my fea from freecad into paraview and use paraview tools to do whatever paraview does haha
i also want to learn calculix.
thanks for your help
Yes, results of simulation performed in FreeCAD FEM can be exported to .vtk format supported by ParaView. Then you have many more postprocessing tools if needed.
All preprocessors only prepare the .inp files used by CalculiX. Those files are input decks using keywords to describe models. Fortunately, ccx keywords are based on Abaqus ones and thus are extremely user-friendly and descriptive. You can find all the details about the syntax in CalculiX User’s Manual: http://www.dhondt.de/ccx_2.21.pdf
Manually editing them gives you the most control and you can add features not supported by some preprocessors like FreeCAD FEM od PrePoMax. In fact, both of them have built-in keyword editors but it’s sometimes better to just use an external text file editor and submit the analyses using standalone ccx solver (ccx_static.exe).
even i’m not a FreeCAD user but still enjoy watching many video from Danial Iskhakov
This channel also has some interesting videos about FreeCAD FEM: https://www.youtube.com/@anisimopensourceengineerin6129/videos
And there’s a series of tutorials for CfdOF (now also starting to show some electromagnetic simulations with Elmer in FreeCAD): https://www.youtube.com/@techbernd5535/videos
Ok, please forgive me, but i am stil very new to freecad. Once i have my analysis container and have done the basic FEA and received the results back, what item from the tree am i exporting so that paraview can open it?
Here are my goals:
I would like to learn how to prepare and solve a mesh in prepomax as one user had mentioned to try out.
I would like to learn how to use paraview to view the exported freecad file
I would like to use calculix in a more advanced way than just running the solver in freecad
cfd stuff, but i think that is outside of this forum? I have CFDOF workbench and that is a little confusing. I know the math behind CFD from my fluids, thermo, and heat transfer classes, but that doesnt mean i know how to set it up correctly haha. bad practice doesnt make perfect.
in case your interested in knowing my goals for CFD
run a 2d flow of either air or water against a flat plate to get the force in newtons
then move to a 3d case to test a 3d model of blade, weather vane, rocket fin etc, with a slow wind hitting it face on, then continue to move up in wind speed.
I REALLY appreciate all the help i have received from you guys
Yeah, it’s better to ask about it on the FreeCAD forum.
ok, i will export that item from the tree and see what i can do with paraview.
I will also start watching some videos on how to use prepomax to do meshing and solving. With this work flow, where do i add the constraints and forces? inside prepomax?
thanks again. Ill try to slow down the questions and start doing things now
start with a very simple model to check all steps,
like one element or a beam, so it is very easy
to find errors or misetakes and to support or help
yeah, going to start with a simple block and move forward. I have alot to learn
I would focus on doing CAD on FreeCAD, and then all the FEA on Prepomax. Sorry FreeCAD, but the FEA benchmark lack of lot of basic tools and procedures, so to me is best to use Prepomax from start. Check out the Prepomax advisor feature that will lead to make your first analysis as having a tutor on your side.
thank you for this. I will start practicing this work flow. I am still new to freecad. I came from sketchup pro which i love and its how my brain works, but since its hard to do fea on STL files, i had to switch to something that could do STEP.
I will check into the advisor guide and hopefully it can help me out haha
ok, things are strange, maybe its correct but since i have never done it, it seems strange. So i make sure the CCx results is highlighted in the tree, when i go to file export, it picks STL as the export type? is this correct or do i need to export it as a different format?
Wait, i think i found my answer… maybe?
Post-Processing of FEM Results with Paraview - FreeCAD Documentation
You have to choose the right format (.vtk) from the drop-down list there.
lol, sorry, i didnt edit my post fast enough. I found a document that helped. Sorry i didnt catch this first. I usually google for most stuff, but alot of times, nothing ever shows up because this stuff is so specialized.
thank you for taking the time to help me.
Can paraview do any meshing itself or calculating?
No, it’s just a postprocessor. Very advanced though. Salome_meca is more versatile in this regard but also hard to use and relies on ParaView for postprocessing.