FreeCAD as pre-post processor for MBDyn

About the development of the FEM module/workbench.

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josegegas
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Re: FreeCAD as pre-post processor for MBDyn

Post by josegegas »

Kunda1 wrote: Mon Jul 19, 2021 11:33 am
josegegas wrote: Mon Jul 19, 2021 4:43 am The first tutorial is now on Gitlab:
Awesome. Is there a link to a final product so people can see the result?

Yes, the solved simulation is in the Examples folder. I forgot to mention this in the tutorial, my mistake... Will be fixed!
josegegas wrote: Mon Jul 19, 2021 4:43 am https://gitlab.com/josegegas/freecad-mb ... al%201.pdf
Is there a reason why you chose pdf over say markdown? People could make Merge Requests to update the tutorial easier that way... just sayin
The reason is that it is the first time ever I hear the word "markdown" :lol:

Can you please provide some quick guide on how to use markdown for tutorials? Many more tutorias will come, and I would like to create them properly. I also thought it may be a good idea to add the tutorials here:

https://wiki.freecadweb.org/Main_Page

I asked for permission to edit this page but didn´t get a reply yet...
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Kunda1
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Re: FreeCAD as pre-post processor for MBDyn

Post by Kunda1 »

josegegas wrote: Mon Jul 19, 2021 1:47 pm The reason is that it is the first time ever I hear the word "markdown" :lol:

Can you please provide some quick guide on how to use markdown for tutorials? Many more tutorias will come, and I would like to create them properly. I also thought it may be a good idea to add the tutorials here:
Markdown is a pretty popular format, it's what is used on github by default. But you have a point, we can just use the freecad wiki. DM me for access to the wiki, I just need a valid email address and we can get you set up. ;)
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josegegas
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Re: FreeCAD as pre-post processor for MBDyn

Post by josegegas »

Hi.

I've added some more basic tutorials, in case someone is keen to try them and give me opinions on how to improve them or the software...

https://gitlab.com/josegegas/freecad-mb ... 0tutorials

Cheers
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OficineRobotica
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Re: FreeCAD as pre-post processor for MBDyn

Post by OficineRobotica »

josegegas wrote: Mon Jul 26, 2021 2:05 am Hi.

I've added some more basic tutorials, in case someone is keen to try them and give me opinions on how to improve them or the software...

https://gitlab.com/josegegas/freecad-mb ... 0tutorials

Cheers
Nice, You always posted some impressive screen recordings. Another workbench to learn. I'll take a look at the tuts.
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josegegas
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Re: FreeCAD as pre-post processor for MBDyn

Post by josegegas »

OficineRobotica wrote: Mon Jul 26, 2021 8:25 am
josegegas wrote: Mon Jul 26, 2021 2:05 am Hi.

I've added some more basic tutorials, in case someone is keen to try them and give me opinions on how to improve them or the software...

https://gitlab.com/josegegas/freecad-mb ... 0tutorials

Cheers
Nice, You always posted some impressive screen recordings. Another workbench to learn. I'll take a look at the tuts.
Great, thanks.
josegegas
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Re: FreeCAD as pre-post processor for MBDyn

Post by josegegas »

Hi all.

There are already a bunch of (I hope) interesting introductory tutorials in Gitlab, including a closed-loop controller for an inverted pendulum and a parametric crank to analyze the vibrations of a crank-slider.

The aim of this tutorials is to introduce the user to the workflow I've created to model and simulate the mechanical systems.

Regards.
josegegas
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Re: FreeCAD as pre-post processor for MBDyn

Post by josegegas »

Hi

So this has been probably the most challanging part of this project, at least so far. To simulate a CAM-follower such as in this example:

https://www.sky-engin.jp/en/MBDynExampl ... /ex13.html

The thing is that one needs a scalar function containig the shape of the cam. In FreeCAD of course the shape of the cam is determined by the CAD of the cam, so the challanging part was to convert the CAD shape of the cam into a scalar function. It took more than a month but finally got it. The algrithm will take the outer edges of the cam (or any other set of edges from a part), and generate a scalar function that follows the shape enclosed by the edges. This function can then be used for any purpose, in this case moving the followers:

phpBB [video]


The hole thing happens in the "AddScalarFunction" method of the "dynamics" class...
JamesLiu
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Re: FreeCAD as pre-post processor for MBDyn

Post by JamesLiu »

Congratulations! Regarding cam-follower simulation, is it possible to use contact algorithm instead of scalar function?
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Re: FreeCAD as pre-post processor for MBDyn

Post by chrisb »

josegegas wrote: Sun Aug 08, 2021 2:00 pm

Code: Select all

https://www.youtube.com/watch?v=pqiP6OYMcGk
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Kunda1
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Re: FreeCAD as pre-post processor for MBDyn

Post by Kunda1 »

phpBB [video]
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