Simulation of a flexible part using Freecad

About the development of the FEM module/workbench.

Moderator: bernd

Post Reply
Abd
Posts: 1
Joined: Mon Dec 06, 2021 1:48 pm

Simulation of a flexible part using Freecad

Post by Abd »

Hi guys,

I have a 3d cad model of a medical bellow which I am using to generate negative pressure (NP) to suck body fluids. What I am trying to do is to enhance the 3d model of the bellow so that I can rise the generated negative pressure by the bellow. The problem here is that I need a way to get the generated (NP) value AFTER changing the 3d model AND according to the material that I set for the part in the program. So I need a simulation program that can achieve these tasks.

Can you tell me if I can do this with Freecad or should I use a different program?
If it is possible with Freecad please refer me to related explanation videos or posts.Image
Attachments
BELLOW.png
BELLOW.png (144.57 KiB) Viewed 2814 times
User avatar
NewJoker
Veteran
Posts: 3017
Joined: Sun Oct 11, 2020 7:49 pm

Re: Simulation of a flexible part using Freecad

Post by NewJoker »

That's a very interesting but also complex topic for engineering simulation if you want to account for both deformation of the bellow and airflow inside it. In such a case you will have to perform FSI (Fluid-Structure Interaction) simulation and FreeCAD can't do it. You will likely have to perform a co-simulation using two programs - for CFD and for mechanical part. Personally, I'd recommend Abaqus and XFlow but there are also other possibilities.

In FreeCAD you could only simulate mechanical or CFD part of the problem individually but I don't think that's what you want to achieve at the moment.

This example can be interesting for you: https://www.simscale.com/projects/psosn ... llowsflow/

P.S. This topic would fit better in FEM forum (or its CfdOF / CFD subforum): https://forum.freecadweb.org/viewforum.php?f=18
User avatar
NewJoker
Veteran
Posts: 3017
Joined: Sun Oct 11, 2020 7:49 pm

Re: Simulation of a flexible part using Freecad

Post by NewJoker »

bernd wrote:
Can you move this one to FEM forum as well ? I forgot about it.

By the way, I hope that I do the pinging correctly.
chrisb
Veteran
Posts: 53920
Joined: Tue Mar 17, 2015 9:14 am

Re: Simulation of a flexible part using Freecad

Post by chrisb »

NewJoker wrote: Tue Jan 04, 2022 9:35 am Can you move this one to FEM forum as well ?
Done
A Sketcher Lecture with in-depth information is available in English, auf Deutsch, en français, en español.
paul18
Posts: 202
Joined: Sat Jul 19, 2014 7:44 pm
Location: France

Re: Simulation of a flexible part using Freecad

Post by paul18 »

Am I right to think that sucking is generated by the manual compression of the bellow? in other word, it depends on the internal volume of this part (which depends itself on the design, the material stiffness and so on). If so, I propose the following workaround:
  • to impose a displacement of the bellow
  • contact condition must be activated (the solver is non-linear)
  • to get the internal volume; you'll need to calculate it outside freecad using Python for example
  • to bench results; the current design is your reference (the lowest the volume is, the lowest the NP wil be I guess)
Note that your design is axisymetrix, you've to use this feature; then the volume can be easily calculated using Guldin formula.

Not easy topic, but interesting one as ever said
Post Reply