Elmer electrostatics FEM

About the development of the FEM module/workbench.

Moderator: bernd

TadasK
Posts: 5
Joined: Fri Dec 06, 2019 6:21 pm

Elmer electrostatics FEM

Post by TadasK » Fri Dec 06, 2019 6:42 pm

Greetings,

Could somebody provide a description or a video of using Freecad for electrostatic problems?

My main concerns:
1. How to model an enclosed far-field sphere?
2. How to define the relative permittivities of the surfaces?

Thanks in advance,
Ted

OS: Windows 10
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.18.4 (GitTag)
Build type: Release
Branch: releases/FreeCAD-0-18
Hash: 980bf9060e28555fecd9e3462f68ca74007b70f8
Python version: 3.6.6
Qt version: 5.6.2
Coin version: 4.0.0a
OCC version: 7.3.0
Locale: Lithuanian/Lithuania (lt_LT)
User avatar
bernd
Posts: 9017
Joined: Sun Sep 08, 2013 8:07 pm
Location: Zürich, Switzerland

Re: Elmer electrostatics FEM

Post by bernd » Mon Dec 09, 2019 1:13 pm

inside this huge topic are numerous examples. There should be one with electrostatics as well. https://forum.freecadweb.org/viewtopic. ... &start=270

These guys know how to do this in FreeCAD FEM.
m42kus wrote: ping
HoWil wrote: ping
TadasK
Posts: 5
Joined: Fri Dec 06, 2019 6:21 pm

Re: Elmer electrostatics FEM

Post by TadasK » Tue Dec 10, 2019 8:22 pm

Thank you bernd.
bernd wrote:
Mon Dec 09, 2019 1:13 pm
inside this huge topic are numerous examples. There should be one with electrostatics as well. https://forum.freecadweb.org/viewtopic. ... &start=270

These guys know how to do this in FreeCAD FEM.
m42kus wrote: ping
HoWil wrote: ping
User avatar
bernd
Posts: 9017
Joined: Sun Sep 08, 2013 8:07 pm
Location: Zürich, Switzerland

Re: Elmer electrostatics FEM

Post by bernd » Tue Dec 10, 2019 10:07 pm

have you read https://forum.freecadweb.org/viewtopic.php?f=18&t=12212

I would recommend to use 0.19 for FEM.
User avatar
bernd
Posts: 9017
Joined: Sun Sep 08, 2013 8:07 pm
Location: Zürich, Switzerland

Re: Elmer electrostatics FEM

Post by bernd » Fri Dec 13, 2019 7:25 am

HoWil
Posts: 885
Joined: Sun Jun 14, 2015 7:31 pm
Location: Austria

Re: Elmer electrostatics FEM

Post by HoWil » Sat Dec 14, 2019 7:50 pm

Hi Bernd,

I tried to run the model from here (https://forum.freecadweb.org/viewtopic. ... 07#p233996) and found some problems.
The main problem is that the vtk-import seems to be broken in 0.19.

You can test this by opening the model called "FemCalculixCantilever3D_newSolver.FCStd " from the startpage.
+Activate the analysis
+Delete "SolverElmerResult"
+Rerun the simulation with "SolverElmer" (write and rerun)
+Open the new vtk-pipeline -> Mode Surface .... now you see that there is no data included in the vtk-object.

Nevertheless, a result object is generated by elmer. it is locate in the "working directory" folder specified in the analysis object.

Hope this can be easily fixed.
Will try to recreate the model in 0.18
BR,
HoWil

OS: Ubuntu 18.04.3 LTS (GNOME/gnome)
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.19.
Build type: Release
Python version: 3.6.9
Qt version: 5.9.5
Coin version: 4.0.0a
OCC version: 7.3.0
Locale: English/UnitedStates (en_US)
HoWil
Posts: 885
Joined: Sun Jun 14, 2015 7:31 pm
Location: Austria

Re: Elmer electrostatics FEM

Post by HoWil » Sat Dec 14, 2019 7:57 pm

Its the same with a newly built model in
OS: Ubuntu 18.04.3 LTS
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.18.4.
Build type: Release
Python version: 2.7.15+
Qt version: 5.9.5
Coin version: 4.0.0a
OCC version: 7.3.0
Locale: English/UnitedStates (en_US)

The standard model called "FemCalculixCantilever3D_newSolver.FCStd " from the startpage does not work at all with my 0.18.
HoWil
Posts: 885
Joined: Sun Jun 14, 2015 7:31 pm
Location: Austria

Re: Elmer electrostatics FEM

Post by HoWil » Sun Dec 15, 2019 1:19 pm

m42kus wrote: ping
Did you experience any if problems above during your last Gsoc?
User avatar
bernd
Posts: 9017
Joined: Sun Sep 08, 2013 8:07 pm
Location: Zürich, Switzerland

Re: Elmer electrostatics FEM

Post by bernd » Mon Dec 16, 2019 9:04 am

on 0.19 dev version

- run elmer analysis
- close the solver taskpanel
- left click in the white area of the tree view and the result object will be there
- I have no idea why the tree view does not get udated

Would you confirm if it works for you.
User avatar
bernd
Posts: 9017
Joined: Sun Sep 08, 2013 8:07 pm
Location: Zürich, Switzerland

Re: Elmer electrostatics FEM

Post by bernd » Mon Dec 16, 2019 3:52 pm

What make me thinking of a problem is there are only displacements in the result object. No stress at all?! IMHO there was more than just the displacement?


remove txt
case0001.vtu.txt
(42.83 KiB) Downloaded 3 times
Post Reply

Who is online

Users browsing this forum: ickby and 2 guests