## Very Simple Thermal Model of Cylindrical Rod

About the development of the FEM module/workbench.

Moderator: bernd

PerdixInc
Posts: 7
Joined: Tue Dec 24, 2019 4:12 pm

### Very Simple Thermal Model of Cylindrical Rod

Greetings!
I am attempting to make a simple thermal model of a cylindrical rod. The idea is that the problem is essentially one dimensional and you can use the equations in Halliday and Resnik to compare the FEM results. There are only three boundary conditions, both ends and the curved cylindrical surface. By changing the initial temperature, thermal conductivity or flux at the surfaces, you can simulate the effects of heating, insulation, and being in a constant radiative bath.
(1) I cannot create new material in the materials editor, and get the results to come up in the materials window. I've added correct thermal conductivity parameters to the editor, and attempted to save, then re-pull the just entered parameters. It doesnt work.
(2) I cannot ascribe the materials to the cylindrical rod. The examples I've pulled off you tube either dont work, or the presentation is soooo garbled I cannot understand. I am willing to post a simple model in the future.

This problem is not rocket science. Thanks!
PerdixInc

OS: Windows 10
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.18.16131 (Git)
Build type: Release
Hash: 3129ae4296e40ed20e7b3d460b86e6969acbe1c3
Python version: 3.6.6
Qt version: 5.6.2
Coin version: 4.0.0a
OCC version: 7.3.0
Locale: English/UnitedStates (en_US)
Attachments
FreeCad Thermal Test 1223192127.FCStd
Kunda1
Posts: 6440
Joined: Thu Jan 05, 2017 9:03 pm

### Re: Very Simple Thermal Model of Cylindrical Rod

Please use the latest 0.19dev for any FEM based operations
Want to contribute back to FC? Checkout:
#lowhangingfruit | Use the Source, Luke. | How to Help FreeCAD | How to report FC bugs and features
PerdixInc
Posts: 7
Joined: Tue Dec 24, 2019 4:12 pm

### Re: Very Simple Thermal Model of Cylindrical Rod

Hi-thank you for the prompt reply.

I have not made it past the 0.19 pre install. I managed to get the Zip file FreeCAD-0.19_pre downloaded to my machine from https://github.com/FreeCAD/FreeCAD/rele ... g/0.19_pre. I downloaded the file FreeCAD_0.19.19036_x64_LP_12.1.2_PY3QT5-WinVS2015.7z

I started looking around for an .exe file to start the program in the exploded files. I have not found an .exe

If I did not download the proper file, can you send me the correct link and some instructions? I am not getting very far here, and I noticed where one other Gentleman was unable to find an executable for his 0.19 pre.

I did not find a 0.19 dev as you suggested

Thank you
PerdixInc
ulrich1a
Posts: 1920
Joined: Sun Jul 07, 2013 12:08 pm

### Re: Very Simple Thermal Model of Cylindrical Rod

PerdixInc wrote:
Tue Dec 24, 2019 10:40 pm
The FreeCAD.exe is inside of the folder "bin". Scroll down until you find the executable binary between all delivered dlls.

But you may be out of luck. It was reported that the two last published versions have a problem: https://forum.freecadweb.org/viewtopic.php?f=4&t=41929

Ulrich
Posts: 1479
Joined: Sat May 20, 2017 12:06 pm
Location: Germany

### Re: Very Simple Thermal Model of Cylindrical Rod

PerdixInc wrote:
Tue Dec 24, 2019 5:07 pm
(2) I cannot ascribe the materials to the cylindrical rod. The examples I've pulled off you tube either dont work, or the presentation is soooo garbled I cannot understand. I am willing to post a simple model in the future.

This problem is not rocket science. Thanks!
PerdixInc
doubleclick on "steel" in model-tree for adjusting the thermomechanical parameters.
For me your file runs.
thermal.FCStd
test_run.JPG (56.34 KiB) Viewed 289 times
PerdixInc
Posts: 7
Joined: Tue Dec 24, 2019 4:12 pm

### Re: Very Simple Thermal Model of Cylindrical Rod

Hi-thank you for taking a look at me FEM Thermal file. It is nice to know that it worked and that I am not a complete idiot! The actual thermal problem I want to model is quite complicated. This is just a start.

The present version of 0.19 Pre apparently is corrupted, or is an incomplete build. There is no executable file in any "bin" folder. There are other postings on this subject.

What is the probability that you help me obtain a copy of your FreeCad 0.19 build? Can we post it on the FreeCad Forum, or is there another way?

Thank you for your help in this matter

PerdixInc
bernd
Posts: 9020
Joined: Sun Sep 08, 2013 8:07 pm
Location: Zürich, Switzerland

### Re: Very Simple Thermal Model of Cylindrical Rod

PerdixInc wrote:
Wed Dec 25, 2019 7:49 pm
What is the probability that you help me obtain a copy of your FreeCad 0.19 build? Can we post it on the FreeCad Forum, or is there another way?
Just wait a few days and it will be fixed.
PerdixInc
Posts: 7
Joined: Tue Dec 24, 2019 4:12 pm

### Re: Very Simple Thermal Model of Cylindrical Rod

Greetings!
I downloaded the 0.19 as shown below, and I got it extracted and it actually runs! We will see how far I get in the FEM analysis
Now I need a brain stem cell transplant from a proficient FreeCad expert.
Anyone want to make a donation?
Thank you!
PerdixInc

OS: Windows 10 (10.0)
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.19.19066 (Git)
Build type: Release
Branch: master